A weed education program, and the biology and control of spotted knapweed (Centaurea maculosa Lam.) in Montana by Celestine Ann Lacey A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Agronomy Montana State University © Copyright by Celestine Ann Lacey (1985) Abstract: Leafy Spurge (Euphorbia esula L.) and spotted knapweed (Centaurea maculosa Lam.) are introduced perennial weeds infesting over 1.1 million hectares of range and pastureland in Montana. In an effort to stop the spread of these weeds, a statewide weed education program was expanded in 1983; and research was initiated on the biology and control of spotted knapweed in Montana. The educational program utilized newsletters, demonstration plots, field tours, and a ransom program to increase awareness and disseminate information on leafy spurge and spotted knapweed. Herbicide demonstration plots and field tours provided information on weed identification, control, and sprayer calibration. A ransom program was initiated in Sweetgrass County, Montana in 1984. The program led to increased public awareness and control of existing spotted knapweed infestations. The effectiveness of the weed education program was evaluated by surveying landowners in four counties. Results of the survey indicated that landowners attending tours were more aware of the weed problem than those that did not attend tours. The number of landowners utilizing weed control practices was also greater among tour participants. The effect of low rates of picloram (4-amino-3,5,6-tri-chloropicolinic acid) and picloram in combination with 2,4-D ((2,4-dichlorophenoxy)acetic acid) on controlling spotted knapweed was evaluated at two locations in Montana. All rates of picloram significantly reduced spotted knapweed density compared to the control. The persistence of picloram in the soil determines the length of control of spotted knapweed. The reduction of spotted knapweed density resulted in forage increases of 200 to 770 percent. Differential tolerance to 2,4-D was observed in spotted knapweed in field experiments conducted at two locations in Montana. When plants from both locations were grown under identical condidtions in the field, there was no difference in response to 2,4-D. Laboratory studies indicate that uptake and translocation of 14C 2,4-D was the same in both strains of spotted knapweed. The observed tolerance to 2,4-D in the initial field studies appears to be the result of differences in plant vigor. The longevity of viability of spotted knapweed seed in the soil was studied from 1982 through 1984. Results of the seed burial study showed that less than 50 percent of the seed had germinated two years after burial. In field studies, about 65 seed per 0.5 m2 remained viable in soil 26 months after seed production was stopped.  A WEED EDUCATION PROGRAM, AND THE BIOLOGY AND CONTROL OF SPOTTED KNAPWEED (C en tau re a m acu lo sa Lam .) IN MONTANA by C e le s t in e Ann Lacey A t h e s i s s u b m it te d i n p a r t i a l f u l f i l lm e n t o f th e r e q u ir em e n ts f o r th e d eg re e o f M aste r o f S c ien c e in Agronomy MONTANA STATE UNIVERSITY Bozeman, Montana June 1985 i i /V 3 7 ? /- M top . APPROVAL o f a t h e s i s s u bm it te d by C e le s t in e Ann Lacey T h is t h e s i s h as been re a d by e a ch member o f th e t h e s i s com m ittee and h a s been found to be s a t i s f a c t o r y r e g a rd in g c o n te n t , E n g lis h u sag e , f o rm a t , c i t a t i o n s , b ib l i o g r a p h ic s t y l e , and c o n s is te n c y , and i s r e a d y f o r su bm is s io n to th e C o lleg e o f G radu a te S tu d ie s . Approved f o r th e M ajor D epartm en t D ate Head, M ajor D epartm en t / Approved f o r th e C o lleg e o f G radua te S tu d ie s (W ^ ~_______ ___ Date G radua te Dean i i i STATEMENT OF PERMISSION TO USE In p r e s e n t in g t h i s t h e s i s i n p a r t i a l f u l f i l lm e n t o f th e r e q u i r em e n ts f o r a m a s t e r 's d eg re e a t Montana S t a te U n iv e r s i ty , I a g re e t h a t th e L ib ra r y s h a l l make i t a v a i l a b l e to b o rrow e rs u n d e r r u l e s o f th e L ib r a r y . B r i e f q u o ta t io n s from t h i s t h e s i s a r e a l lo w a b le w ith o u t s p e c i a l p e rm is s io n , p ro v id e d t h a t a c c u r a te acknow ledgm ent o f so u rc e i s made. P e rm is s io n f o r e x te n s iv e q u o ta t io n from o r r e p ro d u c t io n o f t h i s t h e s i s may be g r a n te d by my m ajo r p r o f e s s o r , o r in h i s a b s e n c e , by th e Dean o f L i b r a r i e s when, . i n th e o p in io n o f e i t h e r , th e p ropo sed u se o f th e m a t e r i a l i s f o r s c h o la r ly p u rp o s e s . Any copy ing o r u se o f th e m a t e r i a l i n t h i s t h e s i s f o r f i n a n c i a l g a in s h a l l n o t be a llow ed w i th o u t my p e rm is s io n . S ig n a tu r e y f Date VACKNOWLEDGEMENTS I would l i k e to e x p re s s my deep a p p r e c ia t io n to my a d v i s o r , D r. P e te F ay , f o r th e h e lp , en cou rag em en t, and f r i e n d s h ip he o f f e r e d d u r in g my e d u c a t io n . S in c e r e th an k s a r e a l s o e x te n d e d to my com m itte e , K r is H a v s ta d , M ichae l F o le y , and Mike J a ck so n f o r t h e i r a s s i s t a n c e and d i r e c t i o n . I would a l s o l i k e to th an k a l l o f th e members i n th e weed c rew , Dan B u rk h a r t , Tim C h ic o in e , Lee C ob le , Shannon Cox, B i l l D yer, Gary F e l lo w s , B ruce M axwell, S c o t t N is s e n , S a rah S c h e r z e r , and many o th e r s f o r t h e i r e n t h u s i a s t i c s u p p o r t , h e lp , and a d v ic e . W ithou t t h e i r tim e and e n e rg y , t h i s p r o j e c t c o u ld n o t have been c om p le ted . A v e ry s p e c i a l th a n k s to my h u sb an d , Jo h n , f o r h i s i d e a s , s u p p o r t , and en cou rag em en t d u r in g th e p a s t two y e a r s . v i TABLE OF CONTENTS Page APPROVAL................................................................................ i i STATEMENT OF PERMISSION TO USE.............................................................................. ' i i i VITA............................................................................................................................................. iv ACKN OWLEDGEMENTS................................... v TABLE OF CONTENTS.............................................................. v i LIST OF TABLES........................................... -....................................................................... ix LIST OF FIGURES............ ...................................................................................................... x i i i ABSTRACT.................................................................................................................................... xv PREFACE.............. x v i PART 1 THE LEAFY SPURGE AND SPOTTED KNAPWEED PUBLIC EDUCATION PROGRAM....................................................... 1 CHAPTER 1 LITERATURE REVIEW .......................................................' ..................................... 2 I n t r o d u c t io n ............................................................................................. 2 E x te n s io n T echn iq u es ............................................................................... 3 A u d io - v is u a l ................................... 3 D em on s tra tio n P l o t s and Group M ee tin g s ............................ 4 W r i t te n Communication ..................................................................... 5 E v a lu a t io n o f D e l iv e ry S y s tem s .................................................. 5 Summary................................................................................................................ 6 2 EXTENSION TECHNIQUES......................................... ............................................... 8 A b s t r a c t .............................................................................................................. 8 I n t r o d u c t i o n ................................................................... .................................• 9 M a te r ia l s and M ethods................................................................ 10 N ew s le t te r ........................................................ 10 D em on s tra tio n P lo t s and F i e ld T o u rs ...................................... 11 Ransom P rog ram .............................................................................................. 13 R e s u l t s and D is c u s s io n ............................................................................... 14 TABLE OF CONTENTS-C on tinued N e w s le t t e r ....................\ ........................................................ ..................... 14 D em on s tra tio n P lo t s and F i e ld T o u rs ................ 16 Ransom P rog ram .................. 20 Summary.................................................................................................. •.......... .. 21 3 PROGRAM EVALUATION.............................................................. ............................... 23 A b s t r a c t ............................................... 23 I n t r o d u c t i o n ................... 23 M a te r ia l s and M ethods......................................................................... 24 R e s u l ts and D is c u s s io n ............................................................................. 26 Summary......................................................... 34 PART 2 BIOLOGY AND CONTROL OF SPOTTED KNAPWEED.......................................... 35 4 LITERATURE REVIEW................................................................................................ 36 I n t r o d u c t i o n .......................... 36 E f f e c t o f S p o tte d Knapweed on Forage P r o d u c t i o n . ........................................................................................... 39 E f f e c t o f P ic lp ram on C o n t r o l l in g S p o t te d Knapweed.................................................. 40 S p o t te d Knapweed Response to 2 ,4 -D ................................................ 43 Summary................................................................................................................ 46 5 THE EFFECT OF REDUCED' RATES OF P ICLORAM ON THE LONGEVITY OF CONTROL OF SPOTTED KNAPWEED.......... ' ................... 48 A b s t r a c t ................................ 46 I n t r o d u c t i o n ................... 48 M a te r ia l s and M e th o d s .............................................................................. 49 P ic lo ram R ate S tu d y ............... 49 D e te rm in a t io n o f P ic lo ram R es id u es ..................... 52 R e s u l t s and D is c u s s io n ............................................................................. '5 4 P ic lo ram R a te S tu d y .......................................................................... 54 P ic lo ram R esiude S tu d y ........................................ 62 Summary................................................................................................................ 66 6 THE EFFECT OF 2 ,4 -D ON TWO STRAINS OF SPOTTED KNAPWEED..................................................................................................... 68 A b s t r a c t ............................................ 68 I n t r o d u c t i o n .......... ............................................................ 69 M a te r ia l s and M e th o d s . . . , ................... 7Q F ie ld S tu d y ....................... 70 Uptake S t u d i e s ..................................................................................... 71 T r a n s lo c a t io n S t u d i e s .................................................... 74 v i i i TABLE OF CONTENTS (Continued) R e s u l t s .............................................................................................................. 76 F i e ld S t u d i e s ....................................................................................... 76 Uptake S t u d i e s ......................................................................................... 80 T r a n s lo c a t io n S tu d ie s ............................................... 82 D i s c u s s i o n . ................ 84 Summary...............*...................................................... ........................................ 85 ■ 7 SEED LONGEVITY OF SPOTTED KNAPWEED IN MONTANA SOILS....................................................................................................... 87 A b s t r a c t .......................................................................................................................... 87 I n t r o d u c t i o n ....................................................................... 87 M a te r i a l s and M ethods.............................................................................. 88 Seed B u r ia l S tu d y ............................................................................................. 88 C u l tu r a l P r a c t i c e S tu d y ............................................................................... 90 R e s u l t s and D is c u s s io n ................................................................................... 91 Seed B u r ia l S tu d y ...................................................... 91 C u l tu r a l P r a c t i c e S tu d y ............................................................................... 96 Summary............................................................................................................................. 104 SUMMARY.................................................................................... ' . ............................................ 105 REFERENCES CITED........................................ 107 APPENDICES.................................................................... 115 APPENDIX A. NEWSLETTERS..................... 116 APPENDIX B. TABLE 34- LIST OF HERBICIDE DEMONSTRATION PLOTS.......................... 153 APPENDIX C. SURVEY QUESTIONNARIE............................. 165 APPENDIX D. RESEARCH TABLES AND FIGURES 170 ix LIST OF TABLES T ab le s Page 1 . The C o s t o f P u b l is h in g th e L ea fy Spurge News and Knapweed U pd a te ............................................................................................................ 16 2 . H e rb ic id e s Used f o r L eafy Spurge D em on s tra tio n P l o t s i n F o u r te e n L o c a tio n s i n Montana ............................................................... 16 3 . H e rb ic id e s Used f o r S p o tte d Knapweed D em on s tra tio n P l o t s in E ig h t L o c a tio n s i n Montana ....................................................... 17 4- P e r c e n t L ea fy Spurge C o n tro l W ith V a r io u s H e rb ic id e a t S e le c te d C o u n tie s in Montana 12 Months A f te r A p p l i c a t io n ............................................................................................. 17 5 . P e r c e n t S p o t te d Knapweed C o n tro l W ith V a r io u s H e rb ic id e s a t S e le c te d C o u n tie s i n Montana 12 Months A f te r A p p l i c a t io n ....................................................................................................... 18 6 . The Number o f P eo p le A tte n d in g S p o t te d Knapweed and L ea fy Spurge T ou rs D uring 1983 and 1984 ........................................... 19 7 . The Number o f P eop le A tte n d in g Weed T ours H eld in 1980/1981 Compared to th e A tten d an c e a t Weed T ou rs H eld a t th e Same L o c a tio n s in 1983 /1984 ................................................... 20 8 . P e r c e n t o f Landowners Able to R ecogn ize T h a t L eafy . Spurge o r S p o t te d Knapweed Were S e r io u s P rob lem s on T h e ir P r o p e r t y . -............................................................................................................ 27 9 . T re a tm en t M ethods Used by Landowners f o r L eafy Spurge C o n tro l i n Four Montana C o u n t ie s ................................................................. 28 10 . T re a tm en t M ethods Used by Landowners in Four Montana C o u n tie s f o r S p o t te d Knapweed C o n t r o l ......................................... 29 11 . The R e la t iv e Im po rtan ce o f Fou r L i s te d R easons f o r n o t C o n t r o l l in g Weeds a s R a ted by Landowners i n Fou r Montana C o u n t ie s .......................................................................... 30 12 . The M ajor Source o f Weed In fo rm a t io n f o r Landowners in . Four Montana C o u n t i e s . .............................................................. 31 X13 . The Most Im p o r ta n t S t r a t e g i e s th e E x te n s io n S e rv ic e Shou ld U t i l i z e to Improve Weed C o n tro l P r a c t i c e s , a s P e r c e iv e d by Landowners i n Fou r C o u n t ie s ........................................... 33 ■ 14 . The A reas o f Weed R e se a rch Needed a t Montana S t a te U n iv e r s i ty a s P e r c e iv e d by Landowners i n Four Montana C o u n t ie s ...............■....................................... .......................................... 33 15- Number o f M atu re S p o t te d Knapweed P l a n t s p e r 0 .2 5 i n J u ly 1983 and J u ly 1984, 14 and 26 Months A f te r P ic lo ram A p p l ic a t io n a t H arlow ton and Ovando............................... 36 16 . Number o f Immature S p o t te d Knapweed P la n t s p e r 0 .2 5 m ^ i n J u ly 1983 and J u ly 1984, 14 and 26 Months A f te r P ic lo ram A p p l ic a t io n a t H arlow ton and Ovando...................... 56 17 . P e r e n n ia l G ra ss P ro d u c tio n on J u ly 20 , 1984, 26 Months A f te r th e A p p l ic a t io n o f P ic lo ram to C o n tro l S p o t te d Knapweed a t H arlow ton and Ovando............................................. 58 18 . The Number o f F o rb s O th e r Than S p o t te d Knapweed P er 0 .0 9 m ^ in June 1984 , 24 Months A f te r H e rb ic id e A p p l ic a t io n a t H arlow ton and Ovando..................................................... 59 19 . The B iom ass o f Forb S p e c ie s O th e r Than S p o t te d Knapweed, 26 Months A f te r H e rb ic id e A p p l ic a t io n a t H arlow ton and Ovando............................. .................. '............................................ ' 62 2 0 . The P e r s i s t e n c e o f P ic lo ram i n Montana S o i l s a s E s t im a te d by Hamaker e t a l . ( 196?) and T h is R esidue S tudy ............................................................................................................................... 64 21 . L eng th o f Time N ece ssa ry f o r P ic lo ram R e s id u e s to D ec rea se Below th e S e n s i t i v i t y L ev e l (8 ppbw) o f S p o t te d Knapweed S e e d l in g s ............................................................................... 65 22 . I n ju r y R a t in g s f o r S p o tte d Knapweed P la n t s C o l le c te d a t Ovando and H arlow ton 40 Days A f t e r F o l i a r T r e a t ­ m ent W ith D ie th an o lam in e S a l t o f 2 ,4- D............................................. 79 23 . Above Ground Dry W eigh t B iomass o f S p o tte d Knapweed S t r a i n s C o l le c te d from H arlow ton and Ovaindo. P l a n t s were T re a te d W ith 2 .2 4 , 1 .1 2 , and 0 .0 0 k g /h a o f 2 ,4 -D on 6 -2 9 -8 4 and H a rv e s te d on 9 -8 -8 4 ................................................ 80 2 4 . T o ta l DPM1s o f 14c 2 ,4 -D R ecovered Over a 48 Hour P e r io d i n th e L ea f Wash, S o lu t io n , and Leaves E x c ise d From S p o t te d Knapweed P l a n t s C o l le c te d From H arlow ton and Ovando......................................................................................... 81 L is t o f T ab les ( Continued) x i L i s t o f T a b le s (C o n tin u ed ) 25 . The P e r c e n t o f 2 ,4 -D T h a t was Absorbed i n L eaves W ith P ubescence Removed and P ubescence I n t a c t 24 and 48 Hours F o llow in g A p p l i c a t io n ............................. ............................ 81 26 . The C o n c e n tra t io n o f 2 ,4 -D (e x p re s s e d a s DPM's p e r gram o f d ry t i s s u e ) T h a t Was R ecovered i n D i f f e r e n t P a r t s o f S p o tte d Knapweed P l a n t s from H arlow ton (H) and Ovando (O ) , M ontana, 1 ,4 ,8 , and 12 Days F o llow in g A p p l i c a t io n ............................................. 83 27 . The D e n s i ty and Above Ground B iomass o f M ature S p o t te d Knapweed P l a n t s Growing a t H arlow ton and Ovando, M ontana ....................................................................................................... 84 28 . The Amount o f N i t ro g e n , P h o sp h o ru s , and P o ta ss ium in th e S u r fa c e F o o t o f S o i l a t H arlow ton and Ovando, Montana .............................................................................. 85 29 . R ecovery o f B u ried S p o t te d Knapweed Seed Samples in th e Seed B u r ia l S tudy E s ta b l i s h e d on S e p t . 21 , 1982 ■ a t Bozeman and Three F o rk s ............................................................................ 92 30 . P e r c e n t G e rm in a tio n D u ring th e B u r ia l P e r io d , and th e V i a b i l i t y o f Dormant S p o tte d Knapweed Seed i n th e Seed B u r ia l S tudy E s ta b l i s h e d S e p t . 21 , 1982 a t Bozeman and T hree F o rk s ............ .......................................... ' ........................... 93 3 1 . Speed o f G e rm in a tio n and Speed o f E lo n g a tio n In d ex Numbers f o r Seed R ecovered From Bozeman and Three F o rk s 24 Months A f te r B u r i a l ........................................................................ 96 32 . The P r e d ic te d R ate o f D e c lin e o f S p o t te d Knapweed Seed Based on th e R ate o f D e c lin e M easured from A p r i l , 1983 to O c to b e r , 1984. a t H arlow ton and Ovando............ .. 102 33 . The P l a n t D e n s i ty o f S p o t te d Knapweed S e e d lin g s in T re a te d and C o n tro l P lo t s i n June 1983 and June 1984 a t H arlow ton and Ovando.................................................................................... 103 Appendix T ab le s 34« A L i s t o f H e rb ic id e D em on s tra tio n P lo t s ........................................... 153 35 . A L i s t o f A ll S p e c ie s O bserved on S i t e One (Ovando) and S i t e Two (H a r lo w to n ) ...................... .......................................................... 171 36 . M onth ly P r e c i p i t a t i o n D ata f o r H arlow ton and Ovando, Montana From Ju n e , 1982 to O c to b e r , 1984 .......... .............................. 172 37» Mean M onthly T em pe ra tu re s f o r H arlow ton and Ovando, Montana From J u n e , 1982 to O c to b e r , 1984 ...................................... 172 38 . R e p r e s e n ta t iv e S o i l P r o f i l e f o r S i t e One ( Ovando, MT)................................................................................................................................. 173 39 . R e p r e s e n ta t iv e S o i l P r o f i l e f o r S i t e Two (H a r lo w ton, MT)................................................................................................. 173 40 . D iv e r s i t y o f O th e r Forb S p e c ie s 24 Months F o llow in g A p p l ic a t io n o f P ic lo ram a t S i t e One (O vando )............................... 174 41 . D iv e r s i ty o f O th e r Forb S p e c ie s 24 Months F o llow in g A p p l ic a t io n s o f P ic lo ram a t S i t e Two (H a r lo w to n ) ......................... 174 42 . M onth ly P r e c i p i t a t i o n D ata f o r Bozeman and Townsend, Montana from J u n e , 1982 to O c to b e r , 1984 ......................................... 175 43 . Mean M onthly T em pe ra tu re s f o r Bozeman and Townsend, Montana from June ,. 1982 to O c to b e r , 1984 ......................................... 175 44* Changes i n th e S o i l R ese rve o f S p o t te d Knapweed S eeds A f te r Seed P ro d u c tio n was S topped on 6 -2 0 -8 2 W ith ■ V a r io u s C u l tu r a l P r a c t i c e s a t H a r low to n .......................................... 176 45 . Changes in th e S o i l R ese rv e o f S p o t te d Knapweed Seeds A f t e r Seed P ro d u c tio n was S topped on 6 -20 -82 W ith V a r io u s C u l tu r a l P r a c t i c e s a t Ovando.............................................. 176 4 6 . The C o n c e n tra t io n o f ^ 2 ,4 -D (e x p re s s e d a s t o t a l DPM's) T h a t Was R ecovered i n th e L ea f Wash and in D i f f e r e n t P a r t s o f S p o t te d Knapweed P l a n t s From H arlow ton (H) and Ovando (O) I , 4 , 8 , and 12 Days F o llow in g A p p l ic a t io n .................................................................................... 177 x i i L i s t o f T ab les (Continued) x i i i LIST OF FIGURES F ig u re s Page 1 o The L o c a tio n o f 1983 and 1984 H e rb ic id e D em on s tra tio n P l o t s and F i e ld T ou rs in M ontana................. ................................................... 12 2 . The Number o f S u b s c r ip t io n s to th e L eafy Spurge News and Knapweed Update from A p r i l , 1980 to O c to b e r, 1984 ................... 15 3 . The L o c a tio n o f Four C o u n tie s i n Montana T h a t Were S e le c te d f o r th e Weed S u rv e y ..................................................................... .. 25 4» The S t r u c tu r e o f C n ic in (from K e ls ey , 1 9 8 5 ) ........................................... 38 5 . Summary o f 2 ,4 -D M etabo lism by P l a n t s (from Feung e t a l . , 1 9 8 2 ) ................................................................................................. 45 6 . The S ta n d a rd Curve Used f o r th e P ic lo ram B i o a s s a y . . . . ................... 55 7 . The C o r r e l a t i o n Between P e r e n n ia l G rass P ro d u c tio n and M ature S p o t te d Knapweed D e n s i ty a t Ovando............................................... 60 8 . The C o r r e l a t i o n Between P e r e n n ia l G rass P ro d u c tio n and M atu re S p o t te d Knapweed D e n s i ty a t H a rlow to n ......................................... 61 9 . The Amount o f P ic lo ram D e te c te d i n S o i l a t H arlow ton and Ovando 26 Months A f te r P ic lo ram A p p l i c a t i o n . ............................... 63 10 . S p o t te d Knapweed P l a n t P a r t s T h a t Were C o l le c te d to D ete rm ine R eg ion s o f 14 C 2 ,4 -D A ccum u la tio n ............................................ 75 11 . The B o l t H e ig h t o f S p o t te d Knapweed P la n ts C o l le c te d From H arlow ton and Ovando, Montana from June 17 to J u ly 26 , 1984 ................. ................................................... ..................................... .. 77 12 . The P e r c e n t o f S p o tte d Knapweed P l a n t s C o l le c te d From H arlow ton and Ovando T ha t Were F low e rin g from J u ly 11 to A ugust 8 , 1984 ...................................................................................................... 78 13 . P e r c e n t G e rm in a tio n o f Seed B u ried f o r 24 Months a t T h ree F o rk s and Bozeman and th e U nburied C o n t r o l ............................... 94 14« R a te o f R a d ic le E lo n g a tio n in S eed s B u ried f o r 9 and 24 Months a t Bozeman and Three F o rk s , and th e U nburied C o n t r o l ........................ ........................................................................................ ............. 95 x iv 15 . P h o to g ra p h s Showing th e E f f e c t o f Aging on Bozeman Seed ( to p ) Compared to th e UnbUried C o n tro l ( b o t to m ) .............................................................................................................................. 97 16 . Changes i n S p o tte d Knapweed Seed R e se rv e s W ith V a rio u s C u l tu r a l P r a c t i c e s from 0 to 28 Months A f te r Seed P ro d u c tio n Was S topped a t Ovando..................................................................... 98 17 . Changes in S p o t te d Knapweed Seed R e se rv e s w ith V a r io u s C u l tu r a l P r a c t i c e s from 0 to 28 Months A f te r Seed P ro d u c tio n Was S topped a t H a rlow to n .............................................................. 99 18 . The D e c lin e o f V iab le S p o t te d Knapweed Seed R e se rv e s from O to 28 Months A f te r Seed P ro d u c tio n was S to p p e d . ................. 101 Appendix F ig u re s 19- The O x id iz e r E f f i c i e n c y Curves f o r S p o tte d Knapweed L e a v e s ......................................................................................................... .................. .. 178 20 . The O x id iz e r E f f i c ie n c y C urves f o r S p o tte d Knapweed Roo t and Crown M a t e r i a l . . . . . ........................................... ................................... 179 L is t o f F igu re s (Continued) XV ABSTRACT L ea fy Spurge ( E upho rb ia e s u la L .) and s p o t t e d knapweed ( C en tau re a m acu lo sa Lam .) a r e in t r o d u c e d p e r e n n ia l weeds i n f e s t i n g o v e r 1 .1 m i l l i o n h e c ta r e s o f ran g e and p a s tu r e la n d i n M ontana. I n an e f f o r t to s to p th e s p re a d o f th e s e w eeds, a s ta te w id e weed e d u c a t io n program was expanded i n 1983; and r e s e a r c h was i n i t i a t e d on th e b io lo g y and c o n t r o l o f s p o t t e d knapweed i n M ontana. The e d u c a t io n a l program u t i l i z e d n e w s l e t t e r s , d em o n s tra t io n p l o t s , f i e l d t o u r s , and a ransom program to in c r e a s e aw a ren e ss and d is s em in a te in fo rm a t io n on l e a f y sp u rg e and s p o t t e d knapweed. H e rb ic id e d em o n s tra t io n p l o t s and f i e l d t o u r s p ro v id e d in fo rm a t io n on weed i d e n t i f i c a t i o n , c o n t r o l , and s p ra y e r c a l i b r a t i o n . A ransom program was i n i t i a t e d i n S w ee tg ra s s C ounty , Montana in 1984. The program le d to in c r e a s e d p u b l ic aw a ren e ss and c o n t r o l o f e x i s t i n g s p o t t e d knapweed i n f e s t a t i o n s . The e f f e c t i v e n e s s o f th e weed e d u c a t io n program was e v a lu a te d by s u rv e y in g landow ners i n f o u r c o u n t i e s . R e s u l t s o f th e su rv ey i n d i c a t e d t h a t landow ne rs a t t e n d in g to u r s were more aware o f th e weed p rob lem th a n th o se t h a t d id n o t a t t e n d t o u r s . The number o f lan dow ne rs u t i l i z i n g weed c o n t r o l p r a c t i c e s was a l s o g r e a t e r among to u r p a r t i c i p a n t s . The e f f e c t o f low r a t e s o f p ic lo ram (4 -am ino -3 ', 5 ,6- t r i - c h lo r o p i c o l i n i c a c id ) and p ic lo ram in com b in a tio n w ith 2 ,4 -D ( ( 2 , 4 - d ic h lo ro p h e n o x y )a 'c e t ic a c id ) on c o n t r o l l i n g s p o t t e d knapweed was e v a lu a te d a t two l o c a t io n s i n M ontana. A l l r a t e s o f p ic lo ram s i g n i f i c a n t l y red u c ed s p o t t e d knapweed d e n s i ty compared to th e c o n t r o l . The p e r s i s t e n c e o f p ic lo ram in th e s o i l d e te rm in e s th e l e n g th o f c o n t r o l o f s p o t t e d knapweed. The r e d u c t io n o f s p o t t e d knapweed d e n s i t y r e s u l t e d i n f o ra g e i n c r e a s e s o f 200 to 770 p e r c e n t . D i f f e r e n t i a l to le r a n c e to 2 ,4 -D was o b se rv ed i n s p o t t e d knapweed i n f i e l d e x p e r im en ts co nduc ted a t two l o c a t io n s i n M ontana. When p l a n t s from b o th l o c a t i o n s were grown u n d e r i d e n t i c a l c o n d id t io n s i n th e f i e l d , th e r e was no d i f f e r e n c e i n re sp o n se to 2 ,4 -D . L a b o ra to ry s tu d i e s ' i n d i c a t e t h a t u p ta k e and t r a n s l o c a t i o n o f 14C 2 ,4 -D was th e same i n b o th s t r a i n s o f s p o t t e d knapweed. The o b se rv ed to le r a n c e to 2 ,4 -D i n th e i n i t i a l f i e l d s t u d i e s a p p e a r s to be th e r e s u l t o f d i f f e r e n c e s i n p l a n t v ig o r . The lo n g e v i ty o f v i a b i l i t y o f s p o t t e d knapweed se ed i n th e s o i l was s tu d i e d from 1982 th ro u g h 1984 . R e s u l ts o f th e seed b u r i a l s tu d y showed t h a t l e s s th a n 50 p e r c e n t o f th e seed had g e rm in a te d two y e a r s a f t e r b u r i a l . In f i e l d s t u d i e s , a b o u t 65 se ed p e r 0 .5 m2 rem ained v i a b l e i n s o i l 26 m onths a f t e r se ed p ro d u c t io n was s to p p e d . PREFACE Weeds a r e becom ing a m a jo r t h r e a t to th e p r o d u c t i v i t y o f r a n g e la n d i n M o n ta n a . The tw o m o s t t r o u b l e s o m e w eed s i n c l u d e l e a f y s p u rg e ( E u p h o rb ia e s u l a L .) a n d s p o t t e d k n apw eed ( C e n ta u r e a m a c u lo s a L am .). B o th w eed s h av e a m a jo r im p a c t on c a t t l e c a r r y i n g c a p a c i t y o f r a n g e l a n d . L e a fy s p u rg e a n d s p o t t e d k n apw eed r e d u c e th e c a r r y i n g c a p a c i ty by up to 75 and 90 p e r c e n t r e s p e c t i v e ly (A lle y e t a l . , 1984; C h i c o in e , 1 9 8 4 ) . The c o s t to t h e c a t t l e i n d u s t r y i n M on tana i s a p p ro x im a te ly $5*9 m i l l i o n in l o s t f o ra g e p ro d u c t io n (F ren ch and Lacey , 1983; R e i l l y and Kaufman, 1979). The f o l l o w i n g t h e s i s e x a m in e s t h e u s e o f an e d u c a t i o n a l a n d r e s e a r c h p ro g ram on l e a f y s p u rg e a n d s p o t t e d k n apw eed . The m a jo r em ph a s is o f th e t h e s i s work in c lu d e d : (1 ) A p u b l ic e d u c a t io n p rogram was expanded i n 1983 in an e f f o r t to i n c r e a s e aw a re n e s s and c o n t r o l o f l e a f y sp u rg e and s p o t t e d knapweed. The e f f e c t i v e n e s s o f th e p rogram was e v a lu a te d . (2) C hem ica l c o n t r o l o f s p o t t e d knapweed w ith 2 ,4 -D and p ic lo ram w as e v a l u a t e d i n a n e f f o r t t o d e t e rm in e th e o p tim um h e r b i c i d e r a t e n e c e s s a ry to c o n t r o l s p o t t e d knapweed. (3 ) The lo n g e v i ty o f v i a b i l i t y o f s p o t te d knapweed seed i n s o i l h a s n o t b e e n d e t e rm in e d . S t u d i e s w e re c o n t i n u e d t o d e t e rm in e th e l e n g t h o f t im e s p o t t e d k n apw eed s e e d s r e m a in v i a b l e i n s o i l u n d e r n a t u r a l and b u r ie d c o n d i t io n s . PART 1 THE LEAFY SPURGE AND SPOTTED KNAPWEED PUBLIC EDUCATION PROGRAM 2CHAPTER 1 ' LITERATURE REVIEW I n t r o d u c t io n L eafy sp u rg e (E upho rb ia e s u la L . ) and s p o t t e d knapweed (C en tau re a m acu lo sa ) a r e th e two m ost tro u b le som e ra n g e weeds i n M ontana. L eafy sp u rg e c u r r e n t l y i n f e s t s o v e r 221 ,632 ha o f r a n g e la n d in th e s t a t e (N oble e t a l . , 1979) and can re d u c e c a t t l e c a r r y in g c a p a c i ty 50 to 75 p e r c e n t (A l le y e t a l . ,1 9 8 4 ) • The e x te n s iv e r o o t system and v e g e ta t i v e buds o f l e a f y sp u rg e make i t d i f f i c u l t to e r a d i c a t e by c h em ic a l , c u l t u r a l o r m ech an ic a l means (Dunn, 1979; M c In ty re , 1972 ). S p o t te d knapweed c u r r e n t l y o c c u p ie s a b o u t 890 ,000 ha o f r a n g e la n d i n Montana (H a r r i s and C ra n s to n , 1 9 79 ), and an a d d i t i o n a l 13 .8 m i l l i o n ha a r e s u s c e p t ib l e to s p o t t e d knapweed in v a s io n (B u c h e r , 1 9 84 ). The weed re d u c e s c a r r y in g c a p a c i ty by a s much a s 90 p e r c e n t on s e v e r e ly i n f e s t e d s i t e s and can s p re a d r a p i d l y b ecau se i t c o n ta in s an a l l e l o p a t h i c ch em ica l which i n h i b i t s th e g row th o f com peting p l a n t s p e c ie s ( F l e c th e r and Renney , 1963 )• F a c to r s w hich le a d to an i n c r e a s e o f weeds on ran g e la n d a r e : 1 ) th e i n a b i l i t y o f r a n c h e r s to c o r r e c t l y i d e n t i f y n o x io u s weeds and 2 ) ig n o ra n c e o f th e p o t e n t i a l t h r e a t th e in v a d in g p l a n t s po se to l iv e s to c k p ro d u c t io n (B a r r e to and Fay , 1 9 83 ) . In a d d i t i o n , many r a n c h e r s in Montana do n o t have e x p e r ie n c e w ith h e rb ic id e a p p l i c a t i o n . The key to c o n t r o l l i n g b o th l e a f y sp u rg e and s p o t t e d knapweed i s to e d u c a te ii 3 lan d ow ne rs to th e im po rta n c e o f e a r l y d e te c t i o n of" in v a s io n and s u b s e q u e n t t r e a tm e n t . E x te n s io n T echn iq u es E f f e c t i v e e d u c a t io n a l p rogram s h e lp b r id g e th e gap betw een a g r i c u l t u r a l p ro d u c e r s and r e s e a r c h r e s u l t s (M yren, 1964; B r a d f i e ld , 1 9 6 6 ) . The in fo rm a t io n p r e s e n te d m ust m eet th e n eed s and i n t e r e s t s o f a l l c l a s s e s o f p ro d u c e rs from in n o v a to r s to l a t e a d o p te r s and la g g a rd s ( Bohlen e t a l . , 1962 ) . Audio -V is u a l T echn iq u es Mass m edia te c h n iq u e s , su ch a s r a d io and t e l e v i s i o n , a r e u s e f u l f o r r e a c h in g l a r g e numbers o f p eo p le a b o u t a g r i c u l t u r a l c o n c e rn s (D a le , 1954; K e lsey and H ea rn e , 1963; Awa and Van Crowder J r . , 1 9 78 ). These te c h n iq u e s a r e s u i t e d to i n c r e a s in g o v e r a l l p u b l ic aw a reness o f a g r i c u l t u r e ( Coleman e t a l . , 1962 ) , a s w e ll a s p ro v id in g s p e c i f i c in fo rm a t io n to a g r i c u l t u r a l p ro d u c e r s (Brown and C o l l in s ’, 1978; R ockw ell, 1984 )• Changes in m a rk e tin g , p l a n t in g , and h a rv e s t in g s t r a t e g i e s have been a t t r i b u t e d to s p e c i f i c r a d io and t e l e v i s i o n p rog ram s (K ro e tz and C o le , 1978; R ockw e ll, 1 984 ). Computers a r e u s e f u l e d u c a t io n a l t o o l s . There a r e s im p l i f i e d com pu ter p rog ram s which- make c u r r e n t t e c h n ic a l in fo rm a t io n r e a d i l y a v a i l a b l e to co un ty e x te n s io n a g e n ts and a g r i c u l t u r a l p ro d u c e rs (C hase , 1984; H a r r i s o n and R ades, 1974; P a i s l e y , 1 983 ). These p rogram s p ro v id e e a sy a c c e s s to c u r r e n t in fo rm a t io n on m a rk e tin g , w e a th e r , and p ro d u c t io n te c h n o lo g y . C om pu ter-based v id e o t e x t in fo rm a t io n d e l iv e r y sy s tem s a r e s u i t a b l e f o r p ro b lem -so lv in g and d e c is io n -m a k in g " ta s k s w ith s p e c i f i c in fo rm a t io n re q u ir em e n ts ( P a i s l e y , 1 983 ). 4Computer p rog ram s have been d ev e lo p ed which s im u la te a g r i c u l t u r a l s i t u a t i o n s (Amend, 1 9 85 ). Some o f th e s e p rogram s have been u sed to e d u c a te a d u l t s and young p e o p le a b o u t th e v a lu e o f a g r i c u l t u r e . D em o n s tra tio n P l o t s and Group M ee tin g s F ie ld D em on s tra tio n p l o t s a r e e f f e c t i v e t o o l s to show new a g r i c u l t u r a l p r a c t i c e s s in c e v i s u a l com pa rison s o f v a r io u s t r e a tm e n ts can be made e a s i l y (B a r r e to and F ay , 1983; Cunningham and S im e ra l , 1977; W it t , 1 9 68 ) . To be m ost e f f e c t i v e , d em o n s tra t io n p l o t s sh o u ld be e s t a b l i s h e d a t num erous l o c a t i o n s s in c e e n v iro nm en ta l c o n d i t io n s can e f f e c t r e s u l t s . Group m ee tin g s su ch a s symposium s, w orkshops, s em in a rs , f i e l d t o u r s , o r fo rm a l c l a s s e s o f f e r an. o p p o r tu n i ty f o r f a rm e rs and r a n c h e r s to d i s c u s s s p e c i f i c p rob lem s w ith r e s e a r c h and e x te n s io n p e r s o n n e l (B a r r e to and Fay , 1 9 8 3 ) . I n v o lv in g l o c a l p ro d u c e r s i n c r e a s e s i n t e r e s t and a c c e p ta n c e o f. new te c h n iq u e s (W it t , 1 9 6 8 ) . The q u a n t i ty and q u a l i t y o f p u b l i c i t y t h a t p r e c e d e s a p rogram h a s a m ajo r im p a c t on th e s i z e o f •the a u d ie n c e (B a r r e to and Fay , 1983; Cunningham and S im e ra l , 1977; B r a d f i e l d , 1 9 6 6 ) . W r i t te n Communication B u l l e t i n s , f l y e r s , n e w s l e t t e r s , and c i r c u l a r s a r e an e f f e c t i v e way to c r e a t e i n t e r e s t , p u b l ic iz e e v e n ts and d is p e n s e in fo rm a t io n ( B r a d f i e ld , 1966; M yren, 1964; Awa and Van C rowder, 1 9 7 8 ) . To be e f f e c t i v e , th e w r i t t e n m a te r i a l m ust be c o n c is e and m eet th e n eed s and i n t e r e s t s o f th e r e a d e r (K e lsey and H e a rn e , 1963; R e isb e c k , 1 9 8 0 ) . 5P r in t e d m edia a p p e a r s to be more e f f e c t i v e th a n a u d io - v i s u a l com m unica tion f o r r e a c h in g s p e c i f i c a u d ie n c e s ( Awa and Van C rowder, 1 9 7 8 ) . B u l l e t i n s , s h o r t p am ph le ts and n e w s l e t t e r s were more e f f e c t i v e th a n t e l e v is io n : and r a d io i n r e a c h in g low income f a m i l i e s (Awa, 1 9 74 ). D a iry f a rm e rs i n New York s t a t e ra n k ed p r i n t e d media h ig h e r th a n r a d i o , t e l e v i s i o n o r i n t e r p e r s o n a l v i s i t s a s th e m ost e f f e c t i v e e x te n s io n com m unica tion e f f o r t (Awa and Van Crowder J r . , 1 9 7 8 ) . N e w s le t te r s a r e a p r e f e r r e d fo rm o f w r i t t e n com m unication i f c o n c is e , w e ll w r i t t e n and p e r t i n e n t (Brown and C o l l in s , 1978; K e lsey and H ea fn e , 1963; R e isb e ck , 1980; H arshman, 1 9 8 1 ) . Im p o r ta n t a r t i c l e s i n n e w s l e t t e r s sh o u ld be h e a d lin e d to g a in th e a t t e n t i o n o f th e r e a d e r (H arshm an, 1981; R e isb e c k , 1 9 8 0 ) . E v a lu a t io n o f D e l iv e ry System s M ailed q u e s t io n n a i r e s have become a p o p u la r m ethod f o r c o l l e c t i n g su rv ey d a t a . Not o n ly a r e th e y c h e ap e r th a n i n t e r p e r s o n a l s u rv e y s , b u t r e c e n t im provem en ts in p ro c e d u re s f o r c o n d u c tin g m a il su rv ey s s u g g e s t t h a t l im i t a t i o n s o f t h i s m ethod ( su c h a s low r e s p o n s e r a t e s and dependence on s h o r t q u e s t i o n n a i r e s ) can be overcome (D illm an , 1 9 78 ) . The m a il q u e s t i o n n a i r e m ust be w e ll d e s ig n ed to o b ta in an sw e rs from su rv ey p a r t i c i p a n t s . The c o n te n t o f th e S u rvey , r a t h e r th an th e l e n g th , p a p e r c o lo r , o r amount o f p e r s o n a l i z a t i o n , a p p e a r s to d e te rm in e r e s p o n s e r a t e (D illm an , 1 9 7 8 ) . F o llow -up l e t t e r s to m a ile d su rv e y s have been u sed e f f e c t i v e l y to in c r e a s e re sp o n se r a t e s (Kanuk and B e re n so n , '19 7 5 ) . The e f f e c t i v e n e s s o f v a r io u s com m unication . c h a n n e ls f o r t r a n s f e r r i n g a g r i c u l t u r a l in fo rm a t io n h a s been m easured by su rv e y in g 6a g r i c u l t u r a l p ro d u c e r s and r e s e a r c h e r s (Adams and P a r k h u r s t , 1984; Awa and Van Crowder J r . , 1 9 78 ). These su rv e y s i n d i c a t e d t h a t fa rm in g s t r a t e g i e s would be im proved i f th e m ost e f f i c i e n t d e l i v e r y sy stem was s e l e c t e d (Adams and P a r k h u r s t , 1 984 ). The e f f e c t i v e n e s s o f a g iv e n com m unication method v a r i e s a c c o rd in g to th e s i z e o f an i n d iv id u a l f a rm e r 's p ro d u c t io n u n i t (Adams and P a r k h u r s t , 1 9 8 4 ) . I n a d d i t i o n , th e means o f com m unication w hich i s m ost e f f e c t i v e i s d ep en d en t upon th e ty p e o f s u b je c t m a t te r b e ing - d e l i v e r e d (Brown and C o l l in s , 1 9 7 8 ) . F o r ex am p le , th e p r im a ry so u rc e o f p ro d u c t io n in fo rm a t io n f o r l a r g e com m erc ia l fa rm s i s th e C oop e ra tiv e E x te n s io n S e rv ic e and th e u n i v e r s i t y sy s tem . Radio was th e m ost e f f e c t i v e m edia f o r b u s in e s s and management in fo rm a t io n (Brown and C o l l in s , 1 9 7 8 ) . Farm m agaz ines were th e m ost im p o r ta n t so u rc e o f a g r i c u l t u r a l in fo rm a t io n f o r f a rm e rs i n N ebraska ( J a e g e r and R e i f s c h n e i d e r ,1965; Adams and P a r k h u r s t , 1 984 )• However, th o se fa rm in g l a r g e a c re a g e s i n N ebraska r a t e d farm jo u r n a l s h ig h e r th an th o s e m anaging sm a l le r a c re a g e (Adams a n d .P a rk h u r s t , 1 9 8 4 ) . Income l e v e l a l s o a f f e c t s com m unication ch an n e l e f f e c t i v e n e s s . B u l l e t i n s , f l y e r s and n e w s l e t t e r s were more e f f e c t i v e th a n a u d io - v i s u a l media f o r low income f a m i l i e s ( Awa, 1974)• E xpe rim en t s t a t i o n b u l l e t i n s were r a t e d h ig h e r a s in fo rm a t io n c h a n n e ls f o r th o se i n th e m idd le and u p p e r income l e v e l s (Adams and P a r k h u r s t , 1 9 84 ). 1 Summary S p o tte d knapweed and l e a f y sp u rg e a r e th e m ost tro u b le som e ran g e weeds i n M ontana. The key to c o n t r o l l i n g b o th weeds i s to e d u c a te 7l a n d o w n e r s so t h a t e a r l y i d e n t i f i c a t i o n and c o n t r o l o f p i o n e e r i n f e s t a t i o n s o c c u r s . A v a r i e t y o f te c h n iq u e s sh o u ld be u t i l i z e d " t o e d u c a te la n d ow n e rs . A u d io -v is u a l te c h n iq u e s in c lu d in g r a d i o a n d t e l e v i s i o n w i l l i n c r e a s e p u b l ic aw a re n e s s o f th e p rob lem . F i e ld t o u r s and d em o n s tra t io n p l o t s w i l l p e r m i t l a n d o w n e r s to v iew a n d r e c o r d th e r e s u l t s o f v a r i o u s p r a c t i c e s an d p e r m i t a t t e n d e e s t o i n t e r a c t w i t h r e s e a r c h e r s a n d e x te n s io n p e r s o n n e l . N e w s l e t t e r s , e x t e n s i o n b u l l e t i n s a n d c i r c u l a r s can p ro v id e i n t e r e s t e d p e rs o n s w ith a c c u r a te in f o rm a t io n a b o u t s p e c i f i c p ro b lem s . M a il s u rv e y s can be u t i l i z e d to o b ta in in fo rm a t io n a b o u t th e e f f e c t i v e n e s s o f v a r io u s com m un ica tio n te c h n iq u e s . U t i l i z i n g th e m o s t e f f e c t i v e c o m m u n ic t io n m e th o d s c a n s a v e m oney by a l l o w i n g e d u c a to r s to key in on s p e c i f i c a u d ie n c e s . 8CHAPTER 2 EXTENSION TECHNIQUES A b s t r a c t An o n -g o in g s ta t e w id e weed e d u c a t io n p rogram was expanded i n 1983. . The o b j e c t i v e s o f t h e p ro g ram w e re to c o n t i n u e th e l e a f y s p u rg e a w a r e n e s s e f f o r t s t a r t e d i n 19 8 0 , a n d i n i t i a t e a s i m i l a r e f f o r t on s p o t t e d knapweed. N e w s le t t e r s , h e r b ic id e d em o n s t ra t io n p l o t s , f i e l d t o u r s a n d a ra n som p ro g ram w ere t e c h n i q u e s u t i l i z e d to m ee t t h e o b j e c t i v e s . L e a fy s p u rg e a n d s p o t t e d k n apw eed n e w s l e t t e r s p r o v id e d , i n f o r m a t i o n on c u r r e n t r e s e a r c h p r o g r a m s an d r e s e a r c h r e s u l t s to a g r i c u l t u r a l p ro d u c e r s , r e s e a r c h e r s , a n d e x t e n s i o n s p e c i a l i s t s . F i e l d p l o t s w ere e s t a b l i s h e d a t tw e n ty - tw o lo c a t io n s , to d em o n s tra te h e rb ic id e e f f i c a c y . F i e l d t o u r s w e re h e ld i n tw e n t y - s i x l o c a t i o n s . The t o u r s i n c l u d e d i n f o r m a t i o n on t h e b i o l o g y a n d c o n t r o l o f l e a f y s p u rg e a n d s p o t t e d k n a pw e ed , h e r b i c i d e e f f i c a c y , a n d s p r a y e r c a l i b r a t i o n . A ransom p rog ram on s p o t t e d knapweed was i n i t i a t e d i n S t i l lw a t e r County , M ontana. The ransom program le d to in c r e a s e d aw a re n e s s o f s p o t t e d knapw eed , c o n t r o l o f e x i s t i n g knapweed i n f e s t a t i o n s , and c o m p i la t io n o f a map d e l i n e a t i n g e x i s t i n g s p o t t e d k n apw eed i n f e s t a t i o n s . The o v e r a l l e d u c a t i o n p ro g ram i n c r e a s e d p u b l ic aw a re n e s s o f l e a f y sp u rg e and s p o t t e d knapweed, e s t a b l i s h e d l o n g - t e rm d e m o n s t r a t i o n p l o t s , a n d s e rv e d a s th e c a t a l y s t f o r s e v e r a l l o c a l i z e d weed a c t i o n p r o j e c t s . I n t r o d u c t i o n L e a fy s p u rg e a n d s p o t t e d k n apw eed a r e m a jo r t h r e a t s to th e p r o d u c t i v i t y o f r a n g e a n d p a s t u r e l a n d i n M on ta n a . The k ey to c o n t r o l l i n g b o t h w eed s i s e a r l y d e t e c t i o n a n d t r e a tm e n t . T h u s , i n 1983, an e d u c a t io n a l p rogram was i n i t i a t e d to h e lp d e c re a s e th e r a t e o f s p r e a d o f l e a f y s p u rg e a n d s p o t t e d k n apw eed i n t h e s t a t e . The o v e r a l l o b j e c t iv e was to i n c r e a s e p u b l ic aw a re n e s s o f s p o t t e d knapweed a n d l e a f y s p u r g e . S p e c i f i c a l l y , th e l e a f y s p u rg e n e w s l e t t e r w as c o n tin u e d and a n e w s l e t t e r on s p o t t e d knapweed was i n i t i a t e d , a ransom p rog ram was s t a r t e d , d em o n s t r a t io n p l o t s were e s t a b l i s h e d , and f i e l d t o u r s were co n d u c ted . C om m u n ic a t i o n t e c h n i q u e s m u s t be e f f e c t i v e t o t r a n f e r t e c h n o lo g ic a l advances to a g r i c u l t u r a l p r o d u c e r s . N e w s l e t t e r s a r e a p re fe r r ed form o f w r i t t e n communication i f they are c o n c is e and r e l a t e t o th e n e e d s and i n t e r e s t s o f th e r e c e i v e r ( Awa,1974 , Brown, 1 978 , Kelsey , 1963, and R eisbeck 1980. Barreto (1982) u t i l i z e d a n ew s l e t t e r t o i n c r e a s e p u b l i c a w a r e n e s s , c o o r d i n a t e r e s e a r c h and p r o v i d e in fo rm a t ion to peop le i n t e r e s t e d i n l e a f y spurge c o n t r o l . ■ D em on s tra tio n p l o t s a r e an e f f e c t i v e e d u c a t io n a l t o o l (Cunningham and S im e r a l , 1 9 7 7 ) , i f t h e p r a c t i c e s 'b e in g d e m o n s t r a t e d p r o v id e p r a c t i c a l s o lu t i o n s to l o c a l p ro b lem s (K e lsey and H ea rn e , 1963). T h is a l lo w s a g r i c u l t u r a l p ro d u c e rs to v iew and r e c o rd th e r e s u l t s o f v a r io u s t r e a tm e n t s u n d e r l o c a l e n v i r o n m e n t a l c o n d i t i o n s ( W i t t , 1 9 6 8 ) . F i e l d t o u r s h e ld a t d em o n s t ra t io n s i t e s p ro v id e an in fo rm a l s e t t i n g where f a r m e r s a n d r a n c h e r s c a n d i s c u s s p r o d u c t i o n p r o b le m s w i t h e x t e n s i o n s p e c i a l i s t s a n d r e s e a r c h e r s ( B a r r e t o a n d F ay , 1 9 8 3 ) . H ow ev e r , f i e l d 9 - 10 t o u r s m u s t be c a r e f u l l y p la n n e d t o m e e t t h e n e e d s and i n t e r e s t s o f p r o d u c e r s (K e ls e y a n d H e a r n e , 1 963 ) a n d be w e l l a d v e r t i s e d t o be e f f e c t i v e (Cunningham and S im e r a l , 1977). M a te r i a l s and M ethods N e w s le t te r s L e a fy S p u rg e N e w s l e t t e r : P u b l i c a t i o n o f t h e L e a fy S p u rg e N e w s le t te r was c o n tin u e d on a q u a r t e r l y b a s i s . The g e n e ra l fo rm a t and m e th o d o lo g y f o r p r i n t i n g th e n e w s l e t t e r w as d e s c r i b e d by B a r r e t o ( 1982 ) . K napw eed U p d a te : A l e t t e r was s e n t t o r e s e a r c h e r s a n d e x t e n s i o n s p e c i a l i s t s i n Id ah o , W ash ing ton , O re g o n , M o n ta n a , B r i t i s h C o lu m b ia , a n d A l b e r t a i n S e p te m b e r , 1983 t o d e t e rm in e i f t h e r e w as a n e e d f o r a n e w s l e t t e r a b o u t th e knapw eeds. These s p e c i a l i s t s p ro v id e d s u g g e s t io n s f o r t h e f o rm a t o f th e n e w s l e t t e r a n d n am es o f e x t e n s i o n a g e n t s , r e s e a r c h e r s , p o l i t i c i a n s , weed s u p e r v i s o r s , and a g r i c u l t u r a l p ro d u c e rs f o r th e i n i t i a l m a i l in g l i s t . A m a i l in g l i s t was s to r e d on a com pu te r d i s k and u p d a te d m on th ly a s r e q u e s t s f o r th e n e w s l e t t e r were r e c e iv e d . The a r t work f o r th e l e t t e r h e a d and r e t u r n a d d re s s was d ev e lo p ed and a s i l k s c r e e n o f t h e d r a w in g w as p ro d u c e d by t h e p h o t o g r a p h i c d e p a r tm e n t a t M on tan a S t a t e U n i v e r s i t y . The l e t t e r h e a d a n d r e t u r n a d d re s s was p r i n t e d by th e M u l t i l i t h D epa rtm en t. R e s e a r c h e r s a n d e x t e n s i o n s p e c i a l i s t s . w e r e c o n t a c t e d f o r c o n t r i b u t i o n s one m o n th p r i o r to p r i n t i n g th e n e w s l e t t e r s . The a r t i c l e s w ere sum m arized , ty p ed , and s e n t to th e M u l t i l i t h D ep a rtm en t f o r p r i n t i n g o n to th e l e t t e r h e a d p a p e r . 11 D em o n s tra tio n P l o t s and F i e ld T ours H e r b i c i d e t r e a tm e n t s w e re a p p l i e d to s p o t t e d k n apw eed o r l e a f y s p u rg e a t tw e n ty tw o s i t e s i n J u n e , 1983 a n d 19§4 ( F ig u r e 1 ) . S i te - l o c a t i o n s w e re s e l e c t e d by c o u n ty e x te n s io n a g e n ts , weed s u p e r v i s o r s an d c h e m ic a l com pany r e p r e s e n t a t i v e s . The s i t e s w e re e a s i l y a c c e s s i b l e a n d l o c a t e d n e a r p o p u l a t i o n c e n t e r s when p o s s i b l e . P i c l o r a m , ( 4 - a m i n o - 3 , 5 ,6- t r i c h l d r o p i c o l i n i c a c i d ) , d ic am b a ( 3 , 6 - d i c h l o r o - o - a n i s i c a c i d ) a n d 2 , 4 -B [ ( 2 ,4-d ic h lo ro p h e n o x y ) a c e t i c a c id ] w e re a p p l i e d to p l o t s a t e a c h s i t e . The t r e a tm e n t s w e re n o t r e p l i c a t e d . I n d iv id u a l p l o t s i z e v a r i e d from 6.6 X 26.6 m e te rs to 6 .6 X 3 6 .3 m e t e r s . The h e r b i c i d e r a t e s a n d a p p l i c a t i o n t im in g w e re recommended by weed s p e c i a l i s t s a t Montana S t a te U n iv e r s i ty , c h em ic a l company r e p r e s e n t a t i v e s , and coun ty e x te n s io n a g e n ts . Ret r e a tm e n ts w ere made on a p o r t i o n o f th e p l o t s i n 1984 . A d e t a i l e d d e s c r i p t i o n o f h e r b ic id e d em o n s t r a t io n p l o t s a t e a ch l o c a t io n i s shown in Appendix B. Twenty s ix f i e l d t o u r s were h e ld in 1983 and 1984 (F ig u re 1). E ig h te e n o f th e t o u r s w ere h e ld a t h e r b ic id e d em o n s t r a t io n l o c a t io n s e s t a b l i s h e d i n 1983 a n d 19 8 4 . The r e m a in d e r o f t h e t o u r s w e re h e ld a t l o c a t i o n s w h ich c o n ta in e d e x p e r im e n ta l p l o t s t h a t w e re p r e v i o u s l y e s t a b l i s h e d ( B a r r e t o , 1982). L oca l la n d ow n e rs , co u n ty e x te n s io n a g e n ts , weed s u p e rv i s o r s , and s t a t e a n d f e d e r a l e m p lo y e e s h e lp e d p l a n an d e x e c u t e t h e . e d u c a t i o n a l ' p r o g r a m . T h is i n t e g r a t e d a p p r o a c h h e lp e d im prove p u b l ic r e l a t i o n s and in c r e a s e d th e o v e r a l l e f f e c t i v e n e s s o f th e p rog ram . > ° | '° '0 I ' «0 XJ L J Fie ld Tou r s © Her b i c i de Demons t r a t i on Plot s F ig u r e I : The L o c a t io n o f 1983 an d 1984 H e r b ic id e D e m o n s t r a t i o n P l o t s and F ie ld Tours in Montana. I' I n fo rm a t io n on th e b io lo g y and d i s t r i b u t i o n o f b o th l e a f y sp u rg e a n d s p o t t e d k n apw eed w as p r e s e n t e d a t e a c h t o u r . The e d u c a t i o n a l p ro g ram s em ph a s ized : 1) An u p d a te and f a c t s on b i o lo g i c a l c o n t r o l ; 2) l e a f y s p u rg e c o n t r o l w i t h s h e e p ; 3 ) e c o n o m ic s o f v a r i o u s c o n t r o l m e a s u r e s ; 4 ) h e r b i c i d e e f f i c a c y ; a n d 5 ) c u r r e n t r e s e a r c h p r o g r a m s . S p ra y e r c a l i b r a t i o n o f hand h e ld and f i e l d s p r a y e r s was d em o n s tra te d a t t o u r s h e ld d u r in g 1984» D is p la y s on coun ty weed c o n t r o l eq u ipm en t and th e l a t e s t i n n o v a t i o n s i n h e r b i c i d e a p p l i c a t o r s f o r a l l t e r r a i n v e h ic l e s (M axw ell e t a l . , 1984) were shown a t th e to u r s . R a d io p r o g r a m s , n ew s a r t i c l e s , a n d f l y e r s w e re u t i l i z e d a s p u b l i c i t y f o r th e t o u r s . G reg N o r t h c u t t , e d i t o r f o r th e M on tan a A g r i c u l t u r a l E x p e r im e n t S t a t i o n , c o n d u c te d th e r a d i o i n t e r v i e w s a n d c o o rd in a te d new s r e l e a s e s . County e x te n s io n a g e n ts i n s e v e r a l c o u n t i e s h a n d le d th e news r e l e a s e s . F ly e r s w ere made and s e n t to te n c o u n t i e s h o l d in g w eed t o u r s . P i c n i c d i n n e r s o r r e f r e s h m e n t s , a n d d o o r p r i z e s w ere p ro v id e d a t e a c h f i e l d to u r by Dow C hem ical Company. Ransom P rogram The c o n c e p t o f a ra n som p ro g ram on s p o t t e d k n apw eed a n d l e a f y sp u rg e was d i s c u s s e d w i th co un ty e x te n s io n a g e n ts . The o b j e c t iv e s o f a weed ransom p rogram were to in c r e a s e aw a re n e s s o f weeds among y o u th and h e lp map co u n ty weed i n f e s t a t i o n s . Young p eo p le p a r t i c i p a t i n g in th e p ro g ram w ere e n c o u r a g e d t o l o c a t e a n d r e p o r t i n f e s t a t i o n s o f l e a f y s p u rg e a n d s p o t t e d k n apw eed to t h e i r c o u n ty e x t e n s i o n a g e n t o r w eed s u p e r v i s o r . Youth who r e p o r t e d new i n f e s t a t i o n s , o r i n f e s t a t i o n s t h a t had n o t been d e n o ted on th e e x i s t i n g co u n ty weed map, w ere aw arded c a sh i n c e n t i v e s . G u id e l in e s f o r th e p rog ram were made by coun ty p e rs o n n e l 13 - 14 t o b e s t m e e t t h e n e e d s o f t h e i r r e s p e c t i v e c o u n ty . The p ro g ram wa s s u p e rv is e d by th e co un ty e x te n s io n a g e n t a n d /o r weed s u p e rv is o r . R e s u l t s and D is c u s s io n N e w s le t te r s N e w s le t t e r s (Appendix A) were d e s ig n e d to p ro v id e in fo rm a t io n to a w ide ra n g e o f a u d ie n c e s . I n fo rm a t io n p r e s e n te d c o v e re d to p ic s su ch a s h e r b i c i d e a p p l i c a t o r s , a l t e r n a t i v e u s e s f o r w eeds, weed m ig r a t io n s , and b i o l o g i c a l , c h em ic a l and c u l t u r a l c o n t r o l m ethods. N e w s le t t e r s a p p e a re d to be an e f f e c t i v e m ethod o f com m un ica tion b e tw een a g r i c u l t u r a l p r o d u c e r s , r e s e a r c h e r s a n d e x t e n s i o n p e r s o n n e l . The num ber o f s u b s c r i p t i o n s to th e L ea fy Spurge N e w s le t te r in c r e a s e d f rom 850 i n O c to b e r , 1981 ( B a r r e t o , 1 982 ) to 1430 by O c to b e r , 1984« S u b s c r i p t i o n s to t h e K napw eed U pd a te i n c r e a s e d f r o m -320 i n O c to b e r , 1983 to 793 i n O c to b e r , 1984 ( F ig u r e 2 ) . The s u b s c r i p t i o n l i s t f o r b o th n e w s l e t t e r s w e re c o m p i le d by r e q u e s t o n ly w h ic h i n d i c a t e s t h e l e v e l o f c o n c e rn f o r s p o t t e d knapweed and l e a f y sp u rg e . T h e re w e re l e s s r e q u e s t s f o r n e w s l e t t e r s f rom f a rm e r s a n d r a n c h e r s t h a n f rom e x t e n s i o n a g e n t s , w eed s u p e r v i s o r s and f e d e r a l em p lo y ees . However, s in c e e x te n s io n p ro v id e s an e f f e c t i v e l i n k b e tw een a g r i c u l t u r a l p ro d u c e rs and r e s e a r c h e r s (Awa and Van C rowder, 1978), th e n e w s l e t t e r b e n e f i t e d th e a g r i c u l t u r a l comm unity i n d i r e c t l y . The c o s t o f p ro d u c in g and m a i l in g th e n e w s l e t t e r i s shown in T ab le 1. The t o t a l c o s t o f th e n e w s l e t t e r would have been much h ig h e r i f s tu d e n t l a b o r and b u lk m a i l in g r a t e s had n o t been u sed . 16 - o o i 4 - x .O 3 CO 6 - O L- Q XJ E 3 Z 0-1_______ 4 / 8 0 4 ” 2 - | I Le a f y S p u r g e News H K n a p w e e d U p d a t e 1 0 / 8 1 I 0 / 8 2 Da t e 0 Ii 1 0 / 8 3 M M N I 0 / 8 4 F ig u re 2: The Number o f S u b s c r ip t io n s to th e Leafy Spurge News and Knapweed Update from A p r i l , 1980 to O c tobe r, 1984. 1 1The Leafy Spurge News was i n i t i a t e d in A p r i l , 1980 and th e Knapweed Update in O c tob e r, 1983. 16 T a b l e I . T he C o s t o f P u b l i s h i n g t h e L e a f y S p u r g e N ew s a n d Knapweed Update from A p r i l 1983 to December 1984 . I t e m C ost ( 4 / 8 3 t o 1 2 / 8 4 ) L eafy Spurge News (7 i s s u e s ) p r i n t i n g and p a p e r $761.00 p o s ta g e a t $ 0 .0 72 /n e w s l e t t e r 655.00 l a b o r 56.00 Knapweed Update (4 i s s u e s ) a r tw o rk 48.00 p r i n t i n g and p ap e r 242.00 p o s ta g e a t $ 0 .0 7 2 /n e w s le t te r 170.00 la b o r 24 .0 0 T o ta l C o st 1956.00 Demonst r a t i o n P l o t s and F ie ld T ou rs H e r b i c i d e d e m o n s t r a t i o n p l o t s w ere an e f f e c t i v e t e c h n iq u e f o r e v a lu a t in g th e e f f e c t i v e n e s s o f v a r io u s h e r b i c id e s f o r l e a f y sp u rg e a n d s p o t t e d k n apw eed c o n t r o l (T a b le 2 a n d 3 ) . P i c lo r a m p r o v id e d th e T a b le 2 . H e r b i c i d e s U sed f o r L e a fy S p u rg e D e m o n s t r a t i o n P l o t s i n F o u r te e n L o c a tio n s i n M ontana. H e r b i c i d e Rate k g / h a p ic lo ram 0.57* p i c I oram 1 .14* p ic lo ram 2 .2 4 dicam ba 2 .2 4 * 2 ,4 - 0 2 .2 4 * * I n d i c a t e s r a t e s t h a t were r e t r e a t e d on 1 /2 o f th e p l o t in 1984 17 T ab le 3« H e rb ic id e s Used f o r S p o tte d Knapweed D em on s tra tio n P l o t s i n E ig h t L o c a tio n s i n M ontana. R ate H e rb ic id e k g /h a p ic lo ram + 0.14 2 ,4 -D 2 .2 4 p ic lo ram 0 .1 4 p ic lo ram 0 .2 8 dicam ba 1 .1 4* 2 ,4 -D 2 .2 4 * * I n d i c a t e s r a t e s t h a t were r e t r e a t e d on 1 /2 o f th e p l o t in 1984. m o s t e f f e c t i v e c o n t r o l o f b o th l e a f y s p u rg e a n d s p o t t e d k n apw eed how ever, p e r c e n t c o n t r o l v a r i e d a c c o rd in g to l o c a t io n (T ab le 4 and 5 ) . T h e se d i f f e r e n c e s w e re p r o b a b ly c a u s e d by v a r i a t i o n s i n s o i l a n d / o r c l im a t i c c o n d i t io n s . R e s u l t s i n d i c a t e th e im p o r ta n c e o f e s t a b l i s h i n g p l o t s in a number o f l o c a t io n s a ro u n d th e s t a t e . T a b le 4» P e r c e n t L e a fy S p u rg e C o n t r o l W ith V a r io u s H e r b i c i d e s a t S e le c te d C o u n tie s in Montana 12 Months A f te r A p p l ic a t io n . P e r c e n t L eafy Spurge C o n tro l R a te County Loca tion" ' Mean^ H e rb ic id e kg /h a P e t . P ow ell C u s te r F a l lo n Da w son X p ic lo ram 0.57 40 95 45 70 95 69 b p ic lo ram 1.14 87 98 95 95 100 95 c p ic lo ram 2.24 99 100 99 99 100 99 c d icam ba 2.24 25 60 10 10 25 26 a 2 ,4 -D 2.24 30 55 15 15 25 28 a ^ P e tro le um coun ty i s a b b r e v ia te d a s P e t . Means fo l lo w e d by th e same l e t t e r a r e n o t s t a t i s t i c a l l y d i f f e r e n t a t th e 5% l e v e l a s d e te rm in e d by th e LSD t e s t o f s i g n i f i c a n c e . 2 18 Tab le 5» P e r c e n t S p o t t e d Knapweed C o n t ro l W ith V a r io u s H e r b ic id e s a t S e l e c t e d C ou n t i e s i n Montana 12 Months A f t e r A p p l i c a t i o n . P e r c e n t S p o t te d Knapweed C on t ro l H e rb ic id e Rate kg /h a F e rg u s County Location"* M u s s e l s h e l l Meagher S i l v e r Bow Mean" X p ic lo r am p i c l o r am + 0.28 0.14 100 100 100 100 100 b 2 ,4-D 2.24 95 95 . 90 95 ' 94 b p ic l o r am 0.14 95 93 90 95 93 b dicamba 1 .1 4 20 45 35 25 31 a 2 ,4 -D .2 .24 15 30 25 20 22 a 1 M u s s e l s h e l l c o un ty i s a b b r e v i a t e d a s M usse l , and S i l v e r Bow coun ty i s a b b r e v i a t e d a s S.B. ^ Means f o l l o w e d by th e same l e t t e r a r e n o t s t a t i s t i c a l l y d i f f e r e n t a t th e 5% l e v e l a s d e te rm in e d by th e LSD t e s t o f s i g n i f i c a n c e . A t t e n d a n c e a t t h e f i e l d t o u r s i n c r e a s e d m ore t h a n tw o f o l d f r om 1980 to 1984. B a r r e t o and Fay (1983) r e p o r t e d an a v e ra g e o f 28 p e r s o n s p e r t o u r i n 1980 a n d 1981 . The a v e r a g e a t t a n d e n c e p e r t o u r i n c r e a s e d t o 57 d u r i n g 1983 a n d 1 984 ( T a b le 6 ) . T h e s e r e s u l t s s u g g e s t t h a t : 1 ) A g r i c u l t u r a l p r o d u c e r s v iew ed th e f i e l d t o u r s a s e f f e c t i v e e d u c a t i o n a l t o o l s ; 2 ) An i n t e g r a t e d a p p r o a c h w h i c h i n v o l v e d e x t e n s i o n a g e n t s , l o c a l l a n d o w n e r s , weed d i s t r i c t s , a n d f e d e r a l a n d s t a t e e m p lo y e e s d u r i n g t h e p l a n n i n g s t a g e f o r t o u r s i n c r e a s e d i n t e r e s t a n d p a r t i c i p a t i o n a t f i e l d t o u r s , a n d 3) I t t a k e s t im e t o i n c r e a s e t h e aw a r e n e s s l e v e l f o r p ro b lem s su ch a s knapweed and l e a f y spu rge . T h i s was e v i d e n t by t h e i n c r e a s e d a t t e n d a n c e a t e a c h o f t h e f i v e c o u n t i e s where r e p e a t t o u r s were h e ld (T ab le ?)• 19 T a b l e 6 . The Number o f P e o p l e A t t e n d i n g S p o t t e d Knapweed a n d L e a fy Spurge Tou rs During 1983 and 1984. 1983 Tours L o c a t io n A ttendance Park 42 R o o s e v e l t 120 V a l le y 45 W heatland 30 F a l lo n 60 Fergus 25 J e f f e r s o n 30 S ande rs 60 M is sou la 70 S i l v e r Bow 30 G a l l a t i n 120 C a r t e r 110 P e t ro le um 41 T o ta l 783 1984 Tours L o c a t io n A ttendance M u s s e l s h e l l 45 P e t ro le um 45 G a r f i e l d 50 R o o s e v e l t 120 V a l ley 40 F e rgu s 30 Cascade 70 P a rk 20 Meagher 50 Bozeman 35 F a l lo n 90 S w e e tg r a s s 100 S i l v e r Bow 25 718T o ta l 20 Tab le 7. L The Number o f P eop le A t te n d in g C om pared t o t h e A t t e n d a n c e a t L o c a t io n s i n 1983/1984. Weed Tours Held Weed T o u r s H e ld i n 1980/1981 a t t h e Same A tten d an c e Date o f Tour L o c a t io n 1980/1981 1983/1984 C a r t e r 6 110 F a l lo n 6 60 M is so u la 30 70" P a rk 25 42 R o o s e v e l t 53 120 'I . S e v e r a l f a c t o r s were im p o r t a n t i n d e t e rm in in g th e a t t e n d a n c e and s u c c e s s o f a weed t o u r : I ) A t ten d an c e was g r e a t e s t a t t o u r s t h a t were 1 I w e l l a d v e r t i s e d . Radio t a p e s , news a r t i c l e s , and f l y e r s sh ou ld be s e n t 'j to c o u n t i e s a t l e a s t t e n days i n advance o f th e t o u r s . 2) A t tendance was g r e a t e s t a t l a t e a f t e r n o o n and e v en in g t o u r s , and l o w e s t a t m orn ing s e s s i o n s . 3 ) The d a te o f th e t o u r m u s t n o t c o n f l i c t w i t h p l a n t i n g o r I h a r v e s t i n g s e a s o n s . 4 ) T ou r s i t e s s h o u l d be e a s i l y a c c e s s i b l e a n d I ; l o c a t e d n e a r p o p u l a t i o n c e n t e r s . !') . ; Ransom Program :- The c o n c e p t o f a weed ransom program was r e j e c t e d by a l l b u t one ; ' Ic o u n t y b e c a u s e o f l a c k o f f u n d i n g . The e x t e n s i o n a g e n t a n d weed . s u p e r v i s o r i n S t i l l w a t e r County e s t a b l i s h e d a ransom program on s p o t t e d k n a pw e ed i n J u n e , 1984« They d e s i g n e d a r a n som p r o g r am w he re y o u t h were p a id $5.00 f o r r e p o r t i n g an i n f e s t a t i o n and an a d d i t i o n a l $50.00 - i i f t h e i n f e s t a t i o n w as c o n t r o l l e d by t h e l a n d o w n e r . C oun ty s p r a y e q u ipm en t was a v a i l a b l e f r e e o f ch a rg e to landow ne rs p a r t i c i p a t i n g w i t h 21 y o u t h i n t h e p r o g r am w h ic h a i d e d c o n t r o l e f f o r t s on t h e k n apw eed i n f e s t a t i o n s . The r a n s om p r o g r am i n S t i l l w a t e r C oun ty w as v e r y s u c c e s s f u l . A pp ro x im a te ly 65 p e o p le were d i r e c t l y in v o lv e d w i t h t h e weed c o n t r o l e f f o r t a s a r e s u l t o f t h e p r o g r a m . P a r t i c i p a n t s i n c l u d e d 14 y oung p e o p le , i n a d d i t i o n to p a r e n t s , a g r i c u l t u r a l p r o d u c e r s , and s t a t e and f e d e r a l e m p l o y e e s . T h i r t y - f o u r s p o t t e d k n apw eed i n f e s t a t i o n s w e re l o c a t e d and r e c o r d e d on th e coun ty weed map which c r e a t e d an a c c u r a t e b a se map f o r th e c oun ty . The p r o g r am w as v e r y e c o n o m i c a l f o r t h e c o u n ty . T o t a l c o s t o f im p lem en t in g th e p rog ram in 1984 was $1170.00. However, by u t i l i z i n g y o u th , r a t h e r th an c oun ty em p loyees to map and c o n t r o l i n f e s t a t i o n s , th e p rog ram a c t u a l l y sav ed th e c oun ty weed c o n t r o l b u d g e t an e s t im a t e d $ 4 500 .0 0 . . T h e r e w i l l a l s o be l o n g - t e r m f i n a n c i a l b e n e f i t s a c h i e v e d t h r o u g h t h e e d u c a t i o n a n d i n v o l v e m e n t o f y o u t h i n t h e weed c o n t r o l e f f o r t . O v e r a l l r e s u l t s o f th e p rogram w ere : 1) An a c c u r a t e map o f s p o t t e d knapweed i n f e s t a t i o n s was d eve loped 2) The l e v e l o f weed aw a r e n e s s weed and c o n t r o l i n c r e a s e d , and 3) The c o s t o f weed c o n t r o l t o t h e c o u n ty d e c r e a s e d . S i x a d d i t i o n a l c o u n t i e s p l a n t o a d o p t a s im i l a r p rogram i n Montana i n 1985. Summary E f f e c t i v e c o m m u n i c a t i o n t e c h n i q u e s a r e i m p o r t a n t w h en i t r a n s f e r r i n g r e s e a r c h r e s u l t s t o a g r i c u l t u r a l p r o d u c e r s . E x t e n s i o n t e c h n i q u e s su ch a s f i e l d t o u r s and d e m o n s t r a t i o n p l o t s can be u t i l i z e d e f f e c t i v e l y a t th e c oun ty l e v e l . N e w s l e t t e r s were an e f f e c t i v e method 22 f o r c o o r d i n a t i n g r e g i o n - w i d e p r o g r a m s an d p r o v i d e c u r r e n t r e s e a r c h i n f o rm a t i o n to e d u c a t o r s . I n n o v a t i v e t e c h n iq u e s su ch a s a weed ransom p r o g r am a r e a n e f f e c t i v e way t o i n c r e a s e weed a w a r e n e s s a n d c o n t r o l e s p e c i a l l y among y o u t h g r o u p s . T h e s e a c t i v i t i e s m u s t be i n t e g r a t e d w i t h r e s e a r c h e r s a n d c o u n ty , s t a t e , a n d . f e d e r a l e n t i t i e s t o e n h a n c e th e o v e r a l l e f f e c t i v e n e s s o f t h e p rog ram . 23 CHAPTER 3 PROGRAM EVALUATION A b s t r a c t A q u e s t i o n n a i r e was d ev e lo p ed to e v a l u a t e th e e f f e c t i v e n e s s o f th e weed e d u c a t io n p rog ram . Three hund red and tw en ty q u e s t i o n n a i r e s were m a i l e d t o p r o d u c e r s t h a t d i d a n d d i d n o t a t t e n d weed t o u r s i n f o u r c o u n t i e s . S i x t y e i g h t p e r c e n t o f t h e s u r v e y s w e re r e t u r n e d . T h e r e was a h i g h e r d e g r e e o f weed a w a r e n e s s among t o u r p a r t i c i p a n t s t h a n among n o n - t o u r p a r t i c i p a n t s . The s u rv ey a l s o p ro v id e d i n f o rm a t i o n on v a r i o u s c o n t r o l m ethods c u r r e n t l y b e in g u sed f o r s p o t t e d knapweed and l e a f y s p u r g e , m a j o r s o u r c e s o f weed i n f o r m a t i o n , r e a s o n s why w eed s w e re n o t b e i n g c o n t r o l l e d , a n d e d u c a t i o n a l a n d r e s e a r c h n e e d s o f p r o d u c e r s i n Montana. I n t r o d u c t i o n E d u c a t i o n a l p r o g r a m s m u s t be e v a l u a t e d t o d e t e r m i n e t h e i r e f f e c t i v e n e s s i n c o m m u n i c a t i n g i n f o r m a t i o n . P r o g r a m s c a n t h e n be m o d i f i e d t o b e s t f i t t h e n e e d s o f t h e a g r i c u l t u r a l c om m un i ty i n an e f f i c i e n t and econom ic manner. M a i l s u r v e y s a r e a common m e th o d f o r g a i n i n g i n f o r m a t i o n f r o m p r o d u c e r s on t h e e f f e c t i v e n e s s o f v a r i o u s c o m m u n i c a t i o n t e c h n i q u e s . B rown a n d C o l l i n s (1 9 7 8 ) s u r v e y e d 1639 f a r m e r s t o d e t e r m i n e t h e i r p r i o r i t i e s o f n e e d f o r v a r i o u s c a t e g o r i e s o f i n f o r m a t i o n , a n d t h e 24 c h a n n e l s o f com m un ica t ion th ey were u s in g to o b t a i n t h a t i n f o rm a t i o n . Adams a n d P a r k h u r s t (1 9 84 ) s a m p l e d 2000 f a r m e r s i n N e b r a s k a t o d e t e rm in e th e im p o r ta n c e o f s e v e r a l c om m un ica t ion c h a n n e l s . J a e g e r and R e i f s c h n e id e r (1965), su rv eyed 2000 f a rm e r s to d e te rm in e t h e i r s o u r c e s o f i n f o rm a t i o n . R e s u l t s o f t h e s e s t u d i e s s u g g e s t t h a t w e l l d e s ig n e d s u r v e y s a r e a n e f f e c t i v e m e th o d f o r a s s e s s i n g v a r i o u s c o m m u n ic a t i o n t e c h n i q u e s . ■ The o b j e c t i v e o f t h i s s u rv ey was to d e te rm in e th e e f f e c t i v e n e s s o f c o m m u n i c a t i o n t e c h n i q u e s u t i l i z e d i n t h e weed e d u c a t i o n p r o g r am . A d d i t i o n a l i n f o rm a t i o n was o b t a i n e d on landow ne rs p e r c e p t i o n o f weed c o n t r o l p r a c t i c e s , h e r b i c i d e u s e , and r e s e a r c h and e x t e n s i o n need s . M a t e r i a l s and Methods F o u r r e p r e s e n t a t i v e c o u n t i e s t h a t h e l d weed t o u r s i n 1983 w e re s e l e c t e d f o r t h e s u r v e y ( F i g u r e 3 ) . L e a f y s p u r g e t o u r s w e re h e l d i n G a l l a t i n and C a r t e r coun ty w h i le s p o t t e d knapweed t o u r s were h e ld i n S a n d e r s a n d M i s s o u l a c o u n t y . A l t h o u g h i n f o r m a t i o n p e r t a i n i n g t o t h e i d e n t i f i c a t i o n and b io lo g y o f b o th weeds was p r e s e n t e d a t e ach t o u r , i n f o rm a t i o n r e g a r d in g l e a f y spu rg e was s t r e s s e d i n G a l l a t i n and C a r t e r c o u n t y , a n d s p o t t e d , k n a pw e ed was s t r e s s e d i n S a n d e r s a n d M i s s o u l a c o u n ty . A su rv ey q u e s t i o n n a i r e was d ev e lo p ed i n O c tob e r , 1983 (Appendix , C). C oun ty e x t e n s i o n a g e n t s f rom t h e f o u r c o u n t i e s a n d a g r i c u l t u r e e d u c a t i o n s p e c i a l i s t s a t Montana S t a t e U n iv e r s i t y r e v iew e d and e d i t e d a s a m p l e q u e s t i o n n a i r e . The q u e s t i o n n a i r e c o u ld be c o m p l e t e d by a r e s p o n d e n t i n l e s s th an 12 m in u te s . ; L i n c o l n I X F ig u re Too l eG l a c i e r P h i l l i p s V o l l e yB l o i n e ,S h e r i d an X__ C h o u l e a u G a r f i e l dC a s c a d eLewi s £ Clork !Petro leum J u d i t h Meagh e r R o s e b u d G ran i t e Golden Valley l F o l l o nC u s t e r C a r t e r B ig Ho rn P owd e r Rive r C a r b o n • • • S P O T T E D KNAPWEED TOURS \ LEAFY SPURGE TOURS 3. The L o c a t io n o f Four C oun t ie s i n Montana T h a t Were S e l e c t e d f o r th e Weed Survey . 26 The q u e s t i o n n a i r e was f i v e p a g e s l o n g i n c l u d i n g a c o v e r l e t t e r e x p l a i n i n g th e su rv ey . The r e t u r n a d d r e s s and p o s ta g e p e rm i t number were p r i n t e d on th e back o f th e q u e s t i o n n a i r e to f a c i l i t a t e m a i l i n g . A l l q u e s t i o n n a i r e s w e re m a rk ed w i t h a n i d e n t i f i c a t i o n n um be r so r e s p o n s e s c o u l d be g r o u p e d by c o u n ty a n d t o u r a t t a n d e n c e . A c o v e r l e t t e r p r i n t e d on Montana S t a t e U n i v e r s i t y l e t t e r h e a d accom pan ied e a ch q u e s t i o n n a i r e and e x p la i n e d th e p u rpo se o f th e su rv ey . P ro d u c e r s t h a t a t t e n d e d e a ch t o u r were m a i le d a q u e s t i o n n a i r e and c o v e r l e t t e r . County a g e n t s w i t h i n t h e f o u r c o u n t i e s th e n s e l e c t e d an e q u a l number o f la n d ow n e rs t h a t had n o t a t t e n d e d th e weed to u r . These p e o p le were s e l e c t e d f rom coun ty ow n e r s h ip maps a n d /o r e x t e n s io n m a i l i n g l i s t s and owned l a n d n e a r known s p o t t e d knapweed o r l e a f y spu rg e i n f e s ­ t a t i o n s . A s u r v e y q u e s t i o n n a i r e a n d c o v e r l e t t e r was a l s o m a i l e d t o t h i s g r o u p . I n J a n u a ry , 1984} 320 q u e s t i o n n a i r e s were m a i le d . A fo l low u p l e t t e r a n d q u e s t i o n n a i r e w e re m a i l e d t o p r o d u c e r s t h a t h ad n o t r e sp o n d ed to t h e i n i t i a l m a i l i n g a f t e r t h r e e weeks. The f i n a l d e a d l i n e f o r r e c e i p t o f th e q u e s t i o n n a i r e s was March I , 1984. R e s p o n s e s t o t h e s u r v e y w e re a s s i g n e d n u m e r i c a l v a l u e s a n d e n t e r e d i n t o th e com pu te r w i th , t h e p a r t i c i p a n t s i d e n t i f i c a t i o n number. S p e c i f i c q u e s t i o n s were a n a ly z e d u s i n g Chi Square a n a l y s i s . R e s u l t s and D i s c u s s i o n , ■' S i x t y - e i g h t p e r c e n t o f th e q u e s t i o n n a i r e s were r e t u r n e d . There was no d i f f e r e n c e i n p e r c e n t r e t u r n be tw een la n dow ne rs t h a t d id and d id n o t a t t e n d weed t o u r s 27 Weed Aw areness Weed aw a re n e s s was s i g n i f i c a n t l y h ig h e r f o r t o u r p a r t i c i p a n t s th an among n o n p a r t i c i p a n t s ( T a b l e 8 ) . T h i s s u g g e s t s f i e l d t o u r s i n c r e a s e d p u b l i c aw a re n e s s o f l e a f y spu rg e and s p o t t e d knapweed. T ab le 8. P e r c e n t o f Landowners Who Were Able to R ecogn ize T h a t L eafy S p u rg e o r S p o t t e d Knapweed Were S e r i o u s P r o b l e m s on T h e i r P r o p e r t y . '. P l a n t S p e c ie s Landowners A t te n d in g Tour Landowners Not A t t e n d in g Tour L ea fy Spurge^ % 100a % 55 b S p o t t e d Knapweed 94a 65 b -I D a ta b a s e d on i n f o r m a t i o n c o l l e c t e d f rom 210 q u e s t i o n n a i r e s r e t u r n e d by Montana l a n d ow n e rs d u r i n g J a n u a r y , 1984 . A bou t o n e - h a l f o f t h e r e s p o n d e n t s d i d a t t e n d a weed t o u r i n 1983 , w h i l e t h e r em a in d e r d i d n o t a t t e n d a weed t o u r i n 1983. p P e r c e n t a g e s i n t h e same row f o l l o w e d by t h e same l e t t e r n o t s i g n i f i c a n t l y d i f f e r e n t a t th e .005 l e v e l . Weed C o n t ro l Survey p a r t i c i p a n t s were a sk ed to i n d i c a t e which c o n t r o l m ethods ' t h ey u sed f o r s p o t t e d knapweed a n d /o r l e a f y spu rg e . T h i r t y p e r c e n t o f th e r e s p o n d e n t s had i n f e s t a t i o n s o f l e a f y sp u rg e . H e r b i c i d e s were t h e m os t im p o r t a n t method o f c o n t r o l f o r b o th g roups o f lan dow ne rs (Tab le 9). However, more t o u r p a r t i c i p a n t s u sed h e r b i c i d e s f o r l e a f y spu rg e c o n t r o l t h a n n o n - t o u r p a r t i c i p a n t s . A bou t f i f t e e n p e r c e n t o f a l l r e s p o n d e n t s w e re u t i l i z i n g some m e th o d o f c o n t r o l o t h e r t h a n t h o s e l i s t e d on t h e q u e s t i o n n a i r e . The o t h e r m e th o d s i n c l u d e d s h e e p (6%), p l a n t i n g c o m p e t i t i v e g r a s s e s ( 1 . 5%) , a n d s p r a y i n g w i t h d i e s e l f u e l (1 .5%) . T h i s s u g g e s t s t h a t l a n d o w n e r s a t t e n d i n g t h e f i e l d t o u r s c o n s i d e r e d l e a f y s p u r g e t o be a p r o b l e m a n d w e re m ore l i k e l y t o a t t e m p t to c o n t r o l i t th an th o s e t h a t d id n o t a t t e n d t o u r s . T ab le 9: T r e a tm e n t Methods Used by Landowners f o r L eafy Spurge C on t ro l i n Four Montana Coun ties /* C o n t r o l Method Landowners A t te n d in g Tour^ Landowners Not A t te n d in g Tour % % M echan ica l 4.8 23.8 B i o l o g i c a l 0.0 ' 4 .7 H e rb ic id e s ^ 95.1a 66 .6b O th e r 9.7 4.7 None 2.4 23-8 1 D a ta b a s e d on i n f o r m a t i o n c o l l e c t e d f rom 210 q u e s t i o n n a i r e s r e t u r n e d by M on tan a l a n d o w n e r s . A b o u t o n e - h a l f o f t h e r e s p o n d e n t s a t t e n d e d a weed t o u r i n 1983. ^ T o t a l p e r c e n ta g e doe s n o t e q u a l 100 because s e v e r a l r e s p o n d e n t s u sed more th a n one t r e a tm e n t method. 3 P e r c e n t a g e s i n t h e same row f o l l o w e d by t h e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e .005 l e v e l . P e r c e n ta g e s n o t f o l l o w e d by a l e t t e r i n d i c a t e numbers t h a t were too sm a l l f o r Chi Squa re a n a l y s i s . S p o t t e d knapweed was l i s t e d a s a p rob lem by 44% o f t h e r e s p o n d e n t s . T h e r e w as no d i f f e r e n c e i n t h e c o n t r o l m e th o d s u s e d f o r s p o t t e d k n a pw e ed by p r o d u c e r s t h a t d i d a n d d i d n o t a t t e n d weed t o u r s ( T a b le 10). H e r b i c i d e s were th e m ost commonly u sed method o f c o n t r o l . The l a c k o f d i f f e r e n c e i n s p o t t e d k n apw eed c o n t r o l b e tw e e n t o u r p a r t i c i p a n t s and th o s e who d id n o t a t t e n d t o u r s may be a r e f l e c t i o n o f th e l e n g t h o f t im e th e knapweed aw a r e n e s s p rogram h a s been i n e f f e c t . The i n t e n s i v e l e a f y spu rg e e f f o r t was i n i t i a t e d i n 1980, however th e s p o t t e d k n apw eed p r o g r am b e g a n i n 1983 . I t may t a k e s e v e r a l y e a r s b e f o r e la n dow ne rs a r e w i l l i n g to a d o p t sound weed management p r a c t i c e s . The l a g p e r i o d a s s o c i a t e d w i t h a d o p t i o n o f new i d e a s h a s b e e n w e l l documen ted (B oh len e t . a l . , 1 962 ) . .T a b l e 10 . T r e a tm e n t M e th o d s Used by L a n d ow n e r s i n F o u r M on tana C oun t ie s f o r S p o t te d Knapweed C o n t r o l .^ C on t ro l Landowners Landowners Not Method A t te n d in g Tours^ A t te n d in g Tours % % M echan ica l^ 25 .5 a 36 .9 a B i o l o g i c a l 19.1 28.3 H e rb ic i d e s 57.0a 54-Oa O th e r 12.7 19.6 None 19.7 21 .7 ^ Data b a sed on i n f o rm a t i o n c o l l e c t e d 1 from 210 q u e s t i o n n a i r e s r e t u r n e d by Montana l a n dow ne rs . About o n e - h a l f o f th e r e s p o n d e n t s a t t e n d e d a weed t o u r in 1983. ^ T o t a l p e r c e n t a g e d o e s n o t e q u a l 100 b e c a u s e s e v e r a l r e s p o n d e n t s l i s t e d two s o u r c e s o f i n f o rm a t i o n a s b e in g th e m ost im p o r ta n t . ^ P e r c e n t a g e s i n t h e same row f o l l o w e d by t h e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e .005 l e v e l . P e r c e n ta g e s n o t f o l l o w e d by a l e t t e r were too sm a l l f o r Chi Square a n a l y s i s . S u r v e y p a r t i c i p a n t s w e re a s k e d t o r a n k f i v e r e a s o n s f o r n o t c o n t r o l l i n g weeds i n Montana. Four p o s s i b l e r e a s o n s were l i s t e d on t h e s u r v e y q u e s t i o n n a i r e . Room f o r a f i f t h m e a s u r e was p r o v i d e d t o p e rm i t r e s p o n d e n t s to l i s t o t h e r c h o ic e s . There was no d i f f e r e n c e i n r e s p o n s e b e tw e e n l a n d o w n e r s t h a t d i d a n d d i d n o t a t t e n d weed t o u r s . Lack o f a v a i l a b l e i n f o rm a t i o n was r an k ed a s th e m ost im p o r t a n t r e a s o n f o r n o t c o n t r o l l i n g w e ed s (T a b le 1 1 ) . T h i s s u g g e s t s t h a t t h e weed 30 c o n t r o l e f f o r t w ou ld be im p r o v e d i f e i t h e r more weed c o n t r o l i n f o r m a t i o n was a v a i l a b l e , o r im p r o v e d m e th o d s f o r d i s t r i b u t i n g , t h e i n f o rm a t i o n to la n dow ne rs was a d op te d . O t h e r r e a s o n s l i s t e d b y l a n d o w n e r s a s i m p o r t a n t f o r n o t c o n t r o l l i n g weeds i n c lu d e d : H igh c o s t o f h e r b i c i d e s (10%), a p a th y (8%), l a c k o f a w a r e n e s s o f t h e weed p r o b l e m (5 .5% ), l a c k o f c o o p e r a t i o n b e tw een la n dow ne rs (3 .5% ) , 'and u n a c c e p t a b l e r e s u l t s f rom p r i o r a t t e m p t s t o c o n t r o l w eeds (2.5%). T a b l e 11. The R e l a t i v e Im p o r t a n c e o f F o u r L i s t e d R e a s o n s f o r n o t C o n t r o l l i n g W eed s a s R a t e d by L a n d o W n e r s i n F o u r Montana C o u n t i e s . -* Reasons f o r n o t c o n t r o l l i n g weeds % o f t o t a l r e s p o n s e s i n d i c a t i n g t h a t th e - r e a s o n was m ost im p o r t a n t ^ Lack o f i n f o rm a t i o n 41 Value o f Land too Low 2? Lack o f A p p l i c a t i o n Equ ipmen t 19 F e a r o f H e r b i c i d e s 15 O the r 22 1 Data b a sed on i n f o rm a t i o n c o l l e c t e d f rom 210 q u e s t i o n n a i r e s r e t u r n e d by lan d ow n e rs d u r in g J a n u a ry , 1984. About o n e - h a l f o f t h e r e s p o n d e n t s a t t e n d e d a weed t o u r i n 1983. ^ T o t a l p e r c e n t a g e - d o e s n o t e q u a l 100 b e c a u s e s e v e r a l r e s p o n d e n t s l i s t e d more th a n one reason* I n f o rm a t io n S o u rc e s S u r v e y p a r t i c i p a n t s w e re a s k e d t o r a n k s e v e n common s o u r c e s o f i n f o r m a t i o n p e r t a i n i n g t o w eed s a c c o r d i n g t o t h e i r v a l u e t o t h e landow ne r (T ab le 12). There was no d i f f e r e n c e i n s o u rc e o f i n f o rm a t i o n 31 be tw een th o s e t h a t d i d and d id n o t a t t e n d weed t o u r s . The c o o p e r a t i v e e x t e n s i o n s e r v i c e was c h o s e n a s t h e m o s t i m p o r t a n t s o u r c e o f weed i n f o r m a t i o n by f i f t y - t w o p e r c e n t o f t h e r e s p o n d e n t s . M on tana S t a t e U n v i e r s i t y was r a n k ed second by 25 p e r c e n t o f th o s e r e s p o n d in g to th e s u rv ey . T h is s u g g e s t s t h a t .p e r s o n a l w i t h in th e c o o p e r a t i v e e x t e n s i o n s e r v i c e a n d r e s e a r c h e r s a t M on tan a S t a t e U n i v e r s i t y s h o u ld work t o g e t h e r i n p r e s e n t i n g t e c h n i c a l i n f o rm a t i o n . Radio o r t e l e v i s i o n was r a n k e d a s m o s t i m p o r t a n t by o n l y f o u r p e r c e n t o f r e s p o n d e n t s . O th e r s o u r c e s o f weed i n f o r m a t i o n i n c l u d e d weed s u p e r v i s o r s (5%), f e d e r a l a g e n c i e s (4%), and p e r s o n a l t r i a l and e r r o r (2%). T h e r e i s u n d o u b t e d l y some b i a s i n t h e r e s u l t s , s i n c e h a l f o f th e s u rv ey p a r t i c i p a n t s a t t e n d e d t o u r s s p o n s o r e d by t h e C o o p e r a t i v e E x t e n s i o n S e r v i c e a n d M o n ta n a S t a t e U n i v e r s i t y . ■ A l s o , s om e p a r t i c i p a n t s t h a t h ad n o t a t t e n d e d w e ed t o u r s w e r e r e c e i v i n g i n f o rm a t i o n f rom th e C oop e ra t iv e E x te n s io n S e rv ic e . T a b l e 12. The M a jo r S o u r c e o f Weed I n f o r m a t i o n f o r L a n d ow n e r s i n Four Montana C oun t ies .^ Source o f I n f o rm a t i o n % o f Landowners C o o p e ra t iv e E x te n s io n S e rv ic e 52 Montana S t a t e U n i v e r s i t y 25 Neighbor 11 A g r i c u l t u r a l B u s in e s s 10 P e r i o d i c a l s 9 N e w s l e t t e r s 5 Radio o r T e l e v i s i o n 4 -I D a ta b a s e d on i n f o r m a t i o n c o l l e c t e d f rom 210 q u e s t i o n n a i r e s r e t u r n e d by Montana la n d ow n e rs d u r i n g J a n u a r y , 1 984» A bou t o n e - h a l f o f th e r e s p o n d e n t s d id a t t e n d a weed t o u r i n 1983, w h i le t h e r em a in d e r d id n o t a t t e n d a weed t o u r in 1983. 32 Farm j o u r n a l s were a l e s s im p o r t a n t so u rc e o f i n f o rm a t i o n i n t h i s s u r v e y (T a b le 12 ) t h a n t h e y w e re i n N e b r a s k a (Adams and P a r k h u r s t , 1 984 ; J a e g e r a n d R e i f s c h n e i d e r 1 9 6 5 ) . The s o u r c e s o f i n f o r m a t i o n l i s t e d i n t h i s q u e s t i o n n a i r e i n c lu d e d fa rm m agaz ines w i t h p e r i o d i c a l s w h i c h .m a y h av e c a u s e d some c o n f u s i o n among s u r v e y p a r t i c i p a n t s . R e s p o n s e s may h av e b e e n d i f f e r e n t i f f a rm m a g a z in e s h ad b e en l i s t e d s e p a r a t e l y . E x te n s io n S t r a t e g i e s S u r v e y p a r t i c i p a n t s w e re a s k e d t o l i s t s t r a t e g i e s t h a t t h e C o o p e r a t iv e E x te n s io n S e r v ic e s h o u ld u t i l i z e t o im p r o v e weed c o n t r o l p r a c t i c e s ( T a b l e 1 3 ) . S i x t y - n i n e p e r c e n t o f t h e r e s p o n d e n t s t h o u g h t t h a t m ore e d u c a t i o n a l p r o g r a m s s u c h a s t o u r s a n d s e m i n a r s s h o u l d be c o n d u c t e d . T h i s i n d i c a t e s t h a t s u r v e y p a r t i c i p a n t s found t o u r s and m ee t in g s to be an e f f e c t i v e com m un ica t ion te c h n iq u e . T h is conc lu s ion , i s s u p p o r t e d by a n e a r l i e r s u r v e y c o n d u c t e d i n G a l l a t i n C oun ty ( C r a n d e l l , P e t r o f f , a n d W olfe* 1983 ) O th e r s t r a t e g i e s i n c l u d e d p u b l i c i z i n g weed p r o b l e m s i n n e w s p a p e r s ' and m ag az in e s , e s t a b l i s h i n g weed n e w s l e t t e r s , p r o v id i n g a c o n s u l t a t i o n s e r v i c e , and f o c u s in g weed c o n t r o l e f f o r t s on lan dow ne rs w i t h sm a l l a c r e a g e s . R e s e a rc h Needs Su rvey p a r t i c i p a n t s were a sk ed t o l i s t i n o r d e r o f im p o r ta n c e w ha t weed r e s e a r c h s h o u ld be c o nd u c te d a t M on tan a S t a t e U n i v e r s i t y ( T a b l e 1 4 ) . S i x t y - t w o p e r c e n t o f t h e s u r v e y p a r t i c i p a n t s r e s p o n d e d t o t h i s q u e s t i o n . R e s e a r c h on b i o l o g i c a l c o n t r o l was r a n k e d a s t h e m o s t im p o r t a n t a r e a by 43% o f t h e r e s p o n d e n t s . Twenty sev en p e r c e n t would l i k e to se e more r e s e a r c h on c o n t r o l o f p e r e n n i a l weeds such a s l e a f y 33 sp u rg e , s p o t t e d knapweed and Canada t h i s t l e ( C irs ium a rv e n s e ) w h i le 26 p e r c e n t w an ted more r e s e a r c h conduc ted on h e r b i c i d e s . R e s e a rch on weed p h y s io lo g y and a l t e r n a t i v e u s e s f o r weeds was ran k ed a s m ost im p o r t a n t by 2% o f t h e r e s p o n d e n t s . T ab le 13. The Most Im p o r t a n t S t r a t e g i e s th e E x te n s io n S e rv ic e Should U t i l i z e to Improve Weed C on t ro l P r a c t i c e s , . a s P e r c e iv e d by Landowners i n Four C o u n t i e s . -* E x te n s io n S t r a t e g i e s % o f Landowners 2 Conduc.t Tours and S em in a rs 69 P u b l i c i z e Weed P rob lem s 15 P u b l i s h N e w s l e t t e r 10 P ro v id e C o n s u l t a t i o n 9 Focus E d u c a t io n on Landowner w i t h Sm a ll A creage 5 "* D a ta b a s e d on i n f o r m a t i o n c o l l e c t e d f rom 210 q u e s t i o n n a i r e s r e t u r n e d by l a n d o w n e r s d u r i n g J a n u a r y , 1984* About o n e - h a l f o f th e r e s p o n d e n t s a t t e n d e d a weed t o u r i n 1983, w h i le th e r em a in d e r d i d n o t a t t e n d a weed t o u r i n 1983« ^ T o ta l p e r c e n ta g e does n o t e q u a l 100 b ecau se s e v e r a l r e s p o n d e n t s l i s t e d two s t r a t e g i e s a s b e in g th e m o s t im p o r t a n t . T a b l e 14» The A rea 's o f Weed R e s e a r c h N eeded a t M on tan a S t a t e U n i v e r s i t y a s P e r c e i v e d by L a n d ow n e r s i n F o u r M on tan a C o u n t i e s . "* R e s e a rc h Needs Lando wners (%) ' B io l o g i c a l C o n t ro l 43 P e r e n n i a l Weed C on t ro l 27 New H e rb ic i d e s 26 Weed P h y s io lo g y 2 A l t e r n a t i v e Uses f o r Weeds 2 *^ D a ta b a s e d o n . i n f o r m a t i o n c o l l e c t e d f r om 130 r e s p o n s e s f r om 210 q u e s t i o n n a i r e s r e t u r n e d by M on tana l a n d o w n e r s d u r i n g J a n u a r y , 1984 . About o n e - h a l f o f th e r e s p o n d e n t s a t t e n d e d a weed t o u r i n 1983- 34 Summary I t a p p e a r s t h a t th e weed e d u c a t io n program h a s been s u c c e s s f u l i n M on ta n a . L a n d ow n e r s t h a t a t t e n d e d weed t o u r s w e re more aw a r e o f t h e l e a f y ' s p u r g e a n d s p o t t e d k n apw eed p r o b l e m s t h a n t h o s e t h a t d i d n o t a t t e n d . A l s o , a t t e m p t s t o c o n t r o l l e a f y s p u r g e w e re s i g n i f i c a n t l y g r e a t e r among t o u r p a r t i c i p a n t s th a n among n o n - p a r t i c i p a n t s . The c o o p e r a t i v e e x t e n s i o n s e r v i c e was l i s t e d a s t h e m os t im p o r t a n t s o u rc e o f weed i n f o rm a t i o n by 52% o f t h e r e s p o n d e n t s . The second m ost i m p o r t a n t s o u r c e o f i n f o r m a t i o n w a s M o n ta n a S t a t e U n i v e r s i t y . R esponden ts f e l t t h a t i f more i n f o rm a t i o n on weed i d e n t i f i c a t i o n and c o n t r o l was a v a i l a b l e i t w o u ld im p r o v e w eed c o n t r o l p r a c t i c e s . Weed t o u r s and s em in a r s were l i s t e d a s im p o r t a n t s t r a t e g i e s f o r t r a n s f e r r i n g weed i n f o rm a t i o n . O th e r im p o r t a n t s t r a t e g i e s i n c lu d e d p u b l i c i z i n g weed p ro b lem s i n n ew sp ap e rs and m agaz in e s , and p u b l i s h i n g weed n e w s l e t t e r s . E d u c a to r s s h o u ld u t i l i z e a r an g e o f com m un ica t ion t e c h n iq u e s to d ev e lo p a sound weed e d u c a t io n p rogram . PART TI. BIOLOGY ANB CONTROL OF SPOTTED KNAPWEED 36 ;>■ ' CHAPTER 4 , • LITERATURE REVIEW I n t r o d u c t i o n S p o t t e d k n a p w e e d ( C e n t a u r e a m a c u l o s a L am .) i s t h e m o s t v t ro u b le som e r a n g e l a n d weed i n w e s t e r n Montana ( IP M Committee M ee ting , 1 9 8 1 ) . The a g g r e s s i v e g r o w t h h a b i t a n d l a c k o f n a t u r a l e n e m ie s h a s a l l o w e d s p o t t e d knapweed to s p re a d r a p i d l y . • S p o t t e d k n apw eed was i n t r o d u c e d t o N o r t h A m e r i c a i n 1893 i n a l f a l f a s e e d f r om A s i a M in o r - T u r k m e n i s t a n (G roh , 1 9 4 0 ) . S p o t t e d knapweed was r e p o r t e d i n R a v a l l i County , Montana by 1920 ( F o r c e l l a and H a rv e y , 1 9 8 0 ) . The weed c u r r e n t l y i n f e s t s a n e s t i m a t e d 8 0 0 ,0 0 0 h e c t a r e s i n t h e s t a t e (M addox , 1979 ) a n d h a s b e e n c o l l e c t e d i n e v e r y coun ty . A pp ro x im a te ly 43 .8 m i l l i o n h e c t a r e s o f g r a z e a b le woodland and r a n g e l a n d i n M on ta n a a r e s u s c e p t i b l e t o s p o t t e d k n apw eed i n v a s i o n (B u c h e r , 1 9 8 4 ). S p o t t e d knapweed i s a b i e n n i a l o r s h o r t - l i v e d p e r e n n i a l h e rb a c eou s p l a n t t h a t ' r e p ro d u c e s from seed . I t h a s numerous a s c e n d in g b r a n c h e s , 3 0 - 1 0 0 cm h i g h , e a c h b e a r i n g a s i n g l e s e e d h e ad (M oore a n d F r a n k t o n , 1974)« The l e a v e s a r e a l t e r n a t e , a n d much d i v i d e d . The u p p e r l e a v e s a r e l i n e a r i n shape . Each f l o w e r head ha s b r a c t s t h a t a r e marked w i t h f i n e v e r t i c a l s t r e a k s a n d . t i p p e d w i t h a b l a c k f r i n g e (W a tso n and Renney, 1974 ). The f l o w e r s a r e t u b u l a r and range i n c o l o r from p u r p le t o w h i t e . S p o t t e d k n apw eed i s a t e t r a p l o i d w i t h n= 18 c h rom o som e s 37 s e e d , v e g e t a t i v e s h o o t s can emerge from 2.5 to 7.5 cm from th e m o th e r p l a n t . These s h o o t s fo rm r o s e t t e s w h ich r em a in a t t a c h e d to th e m o th e r p l a n t (Watson and Renney, 1974). S p o t t e d knapweed r e p r o d u c e s a g g r e s s i v e l y by s e ed . The number o f v i a b l e s e e d p r o d u c e d p e r p l a n t i s d i r e c t l y r e l a t e d t o t h e am o u n t o f a v a i l a b l e m o i s t u r e ( S c h i rm a n n , 1 9 8 1 ) . I n d i v i d u a l s p o t t e d k n apw eed p l a n t s p r o d u c e f r om 436 t o 2 5 ,2 6 3 s e e d s u n d e r d r y l a n d a n d i r r i g a t e d c o n d i t i o n s r e s p e c t i v e l y (Watson and Renney, 1974). The number o f s e e d s p roduced p e r sq u a re m e te r r a n g e s f rom 7000 to 90,000 (Sch irm an , 1984). S to ry (1976) e s t im a t e d t h a t s p o t t e d knapweed p l a n t s p roduce an a v e ra g e o f 1000 s e e d s p e r p l a n t i n M on ta n a . S e ed d i s p e r s a l b e g i n s tw o t o t h r e e w eek s a f t e r f l o w e r i n g . When m ovem en t o f t h e s t em o c c u r s , t h e a c h en e s a r e e x p e l l e d w i t h a f l i c k i n g a c t i o n from th e head . Seeds may l a n d up to one m e te r from th e p a r e n t p l a n t (Watson & Renney, 1974). S p o t t e d k n a p w e e d s e e d s g e r m i n a t e o v e r a b r o a d r a n g e o f e n v i r o n m e n t a l c o n d i t i o n s . W a tson a n d Renney (1 9 7 4 ) f o u n d t h a t c o n t in u o u s l i g h t s i g n i f i c a n t l y r e d u c ed g e rm in a t io n o f s p o t t e d knapweed a f t e r s i x d ay s . Optimum g e rm in a t io n t em p e r a tu r e was 10C to 28 C b u t g e rm in a t io n o c c u r r e d a t . t em p e r a t u r e s f rom 7 C to 34 C. The l o n g e v i t y o f s p o t t e d k n apw eed s e e d v i a b i l i t y h a s n o t b e e n d e te rm in e d . However, p r e l im i n a r y work by Sh irm an (1984) and C h ico in e (1984) i n d i c a t e s t h a t b u r i e d s p o t t e d knapweed seed r em a in v i a b l e i n t h e s o i l f o r more t h a n f i v e y e a r s . S p o t t e d knapweed i s w e l l a d a p te d to a wide r a n g e o f e n v i r o nm en ta l c o n d i t i o n s . The weed h a s been o b se rv ed a t a l t i t u d e s r a n g in g from 30 m to o v e r 2700 m (Watson and Renney, 1974; C h ico in e , 1984) and i n a n n u a l 38 p r e c i p i t a t i o n zones which r e c e iv e l e s s th an 25.4 cm and more th an 200 cm a n n u a l l y (C h ic o in e , 1984). S p o t t e d k n apw eed r e a d i l y c o l o n i z e s s o i l s w i t h a w ide r a n g e o f c h e m i c a l a n d p h y s i c a l p r o p e r t i e s . The d e g r e e o f s o i l d i s t u r b a n c e r a t h e r th an s p e c i f i c s o i l p r o p e r t i e s d e t e rm in e s th e d e n s i t y p o t e n t i a l o f s p o t t e d knapweed (Watson and Renney, 1974). A l though open h a b i t a t s a r e p r e f e r r e d by s p o t t e d k n a pw e ed , (W a tso n and R enney , 1974 ) i t w i l l in v ad e d i s t u r b e d f o r e s t s o i l s which have an i n t e r m i t t e n t canopy c o v e r ( p e r s o n a l o b s e r v a t i o n ) . S p o t te d knapweed p ro du ce s an a l l e l o c h e m i c a l which h e lp s th e p l a n t m a i n t a i n s t a n d d e n s i t i e s ( F l e t c h e r a n d R enney , I 9 6 3 ) . P r e l i m i n a r y s t u d i e s h av e t e n t a t i v e l y i d e n t i f i e d t h e a l l e l o c h e m i c a l a s c n i c i n (K e l s e y , 1984 ) ( F i g u r e 4 ) . The h i g h e s t c o n c e n t r a t i o n o f c n i c i n i s found i n t h e l e a v e s ( F l e t c h e r and Renney, 1963). F ig u re 4- The S t r u c t u r e o f C n ic in ( f rom K e lsey , 1985). 39 E f f e c t o f S p o t t e d Knapweed on F o rage P r o d u c t io n The d e n s e , s p i n y c a n o p y o f s p o t t e d k n a p w e e d r e d u c e s t h e a v a i l a b i l i t y o f d e s i r a b l e f o r a g e s p e c i e s (W a tso n a n d P e n n e y , 1 9 7 4 ) . A l th ough s p o t t e d knapweed i s r a r e l y u t i l i z e d f o r f o r a g e , th e r o s e t t e s o f s p o t t e d knapweed have some n u t r i t i v e v a lu e . The p r o t e i n c o n t e n t o f s p o t t e d knapweed p l a n t s . h a r v e s t e d i n l a t e May i n Montana range from 9 t o 18 p e r c e n t d e p e n d in g on t h e s i t e . ' S p o t t e d k n apw eed mowed i n l a t e s p r i n g has a l s o been found to p roduce a good q u a l i t y s i l a g e w i t h o v e r 19 p e r c e n t p r o t e i n (K e lsey , 1985, p e r s o n a l com m un ic a t io n ) . H o w e v e r , a s t h e p l a n t r e a c h e s , m a t u r i t y , th e n u t r i t i o n a l v a lu e d e c r e a s e s and f i b e r c o n t e n t i n c r e a s e s (K e lsey , 1985, p e r s o n a l c om m un ic a t ion ; F l e t c h e r and R en n ey , 19 6 3 ) . R e c e n t l y , Cox (1 9 8 3 ) r e p o r t e d t h a t s h e e p r e a d i l y c o n sum e s p o t t e d k n apw eed i n a p a s t u r e s e t t i n g . T h i s i n t e r e s t i n g f i n d i n g m e r i t s f u r t h e r r e s e a r c h to d e v i s e methods o f sheep management a s a c o n t r o l method. The c o m p e t i t i v e n a t u r e o f t h e 'k n a pw e e d s h a s been w e l l documented . W a tso n a n d R enney (1 9 7 4 ) f o u n d t h a t k n apw eed i n v a s i o n on a good c o n d i t i o n b l u e b u n c h w h e a t g r a s s ( A g ro p y ro n s p i c a t u m ) - r o u g h f e s c u e (F e s tu c a s c a b r e l l a ) r a n g e l a n d i n Canada r edu ced f o r a g e p r o d u c t i o n 87.5 p e r c e n t , f rom 896 kg /h a to 112 k g /h a . S im i l a r r e s u l t s were r e p o r t e d i n I d a h o a n d M on tan a w h e re s p o t t e d k n apw eed r e d u c e d p e r e n n i a l g r a s s p r o d u c t i o n from 80 to 90 p e r c e n t (W a t te n b a rg e r e t a l . , 1980; C h ic o in e , 1 984 ) . C r e s t e d w h e a t g r a s s (A g ro p y ro n c r i s t a t u r n ) a n d R u s s i a n w i l d r y e (E lymus j u n c e u s ) have been shown to compete w i th s p o t t e d knapweed and d i f f u s e k n apw eed ( C e n t a u r e a d i f f u s a ) . There a r e a l s o u n s u b s t a n t i a t e d 40 r e p o r t s t h a t s h e e p f e s c u e ( F e s t u c a o v i n a ) o c c u r s i n a s s o c i a t i o n w i t h s p o t t e d k n apw eed ( J o h n L a c e y , 1 9 85 , p e r s o n a l c o m m u n i c a t i o n ) . The d e g re e o f knapweed s u p p r e s s io n by g r a s s e s w i l l v a ry a c c o rd in g to th e g r a s s s p e c i e s a n d t h e c l i m a t i c r e g im e . M yers a n d B e ru b e (1 9 83 ) r e s am p le d p l o t s e s t a b l i s h e d i n 1967 to d e te rm in e th e e f f e c t i v e n e s s o f c r e s t e d w h e a tg r a s s ■ and R u s s ia n w i l d r y e i n p r e v e n t i n g r e i n f e s t a t i o n o f d i f f u s e knapweed. R e s u l t s i n 1978 (11 y e a r s f o l l o w in g t r e a tm e n t ) showed d i f f u s e knapweed d e n s i t i e s were h ig h i n n on -se ed ed p l o t s , m odera te i n R u s s ian w i l d r y e p l o t s and v e ry low i n c r e s t e d w h e a tg r a s s p l o t s a t one l o c a t i o n . However, d i f f u s e knapweed had c om p le te ly r e i n v a d e d a s im i l a r e x p e r i m e n t a l s i t e i n a h i g h e r r a i n f a l l z o n e . The a b i l i t y o f c r e s t e d w h e a t g r a s s t o u t i l i z e s o i l m o i s t u r e e a r l y i n t h e s p r i n g a p p e r a n t l y d e p l e t e s t h e s o i l m o i s t u r e r e s e r v e s w h i c h a r e c r i t i c a l f o r s e e d l i n g e s t a b l i s h m e n t o f d i f f u s e knapweed (H u b b a rd , 1975 ; M ye rs a n d B e r u b e , 1 983 ) . C a t t l e c a r r y i n g c a p a c i t y i s r e d u c e d a s s p o t t e d knapweed r e p l a c e s more d e s i r a b l e f o r a g e s p e c i e s . C ra n s to n (1984) e s t im a t e d s to c k in g r a t e l o s s e s due to s p o t t e d knapweed were a p p ro x im a t e ly '$1.5 m i l l i o n a n n u a l l y i n B r i t i s h Columbia. The a n n u a l f o r a g e l o s s . c a u s e d by s p o t t e d knapweed i n M on tan a i s e s t i m a t e d t o be $4 .5 m i l l i o n ( F r e n c h a n d L ac ey , 1 9 8 3 ) . Range l i v e s t o c k income c o u ld be r e d u c e d by $155*7 m i l l i o n a n n u a l l y i f a l l v u l n e r a b l e r a n g e a n d g r a z e a b l e w o o d la n d i n M on tan a was i n f e s t e d ( B u c h e r , 1 984 ) . E f f e c t o f P ic lo r am on C o n t r o l l i n g S p o t te d Knapweed P ic lo r am ( 4 - a m i n o - 3 , 5 , 6 - t r i c h l o r o p i c o l i n i c a c i d ) a n d 2 , 4~D ( [ 2 , 4 - d i c h l o r b p h e n o x y ] a c e t i c a c i d ) h av e b e e n u s e d e x t e n s i v e l y f o r s p o t t e d 41' k n a pw e ed c o n t r o l on r a n g e a n d p a s t u r e l a n d . T h e s e a r e s e l e c t i v e h e r b i c i d e s which c o n t r o l b r o a d l e a f weeds w i th l i t t l e damage to g r a s s s p e c i e s . P i c l o r a m i s t h e m o s t e f f e c t i v e h e r b i c i d e f o r c o n t r o l l i n g s p o t t e d k n apw eed a n d p r o v i d e s f r o m one t o f i v e y e a r s o f c o m p l e t e c o n t r o l ( C r a n s t o n , 1 984 ; C h i c o i n e , 1984)» L i q u i d f o r m u l a t i o n s o f p i c l o r a m a r e more e f f e c t i v e t h a n c o m p a r a b l e r a t e s o f t h e g r a n u l a r f o rm a t i o n s (M a t te n b a rg e r e t a l . , 1980). Renney and Hughes (1969) found t h a t p i c lo r am a p p l i e d a t 0.42 t o 0.56 k g /h a p r o v id e d optimum c o n t r o l o f C en ta u re a s p e c i e s . P ic lo r am a t 0.28 to 1.12 k g /h a p r o v id e d 100 p e r c e n t c o n t r o l o f s p o t t e d knapweed one y e a r f o l l o w i n g h e r b i c i d e a p p l i c a t i o n ( W a t t e n b a r g e r e t a l . , 1 9 8 0 ) . The a d d i t i o n o f 2 .24 k g / h a o f 2 ,4 -D t o 0 .2 8 k g / h a o f p i c l o r a m d i d n o t im p r o v e s p o t t e d k n apw eed c o n t r o l o v e r 0.28 k g /h a o f p i c lo r am a lo n e ( C h ic o in e , 1984). The p e r s i s t e n c e a n d r a t e o f p i c l o r a m i n s o i l d e t e r m i n e s t h e l e n g t h o f c o n t r o l f o r many weed s p e c i e s . The r e s i d u a l p e r i o d o f a c t i v i t y o f p i c l o r a m v a r i e s c o n s i d e r a b l y a t d i f f e r e n t l o c a t i o n s . Goring e t a l . - (1965) r e p o r t e d t h a t d e c om p o s i t io n o f p i c l o r am a p p l i e d a t r a t e s r a n g i n g f rom 1 .57 t o 4-7 k g / h a i n f o u r s t a t e s r a n g e d f rom 78 t o 100 p e r c e n t a f t e r tw o y e a r s . K eys a n d F r i e s e n (1 9 6 8 ) m e a s u r e d t h e r e s i d u a l a c t i v i t y o f p i c lo r am t h r e e y e a r s a f t e r a p p l i c a t i o n on f o u r s o i l s i n w e s te rn Canada. The amoun t o f p i c lo r am r em a in in g i n th e s o i l was 10 p e r c e n t o f th e o r i g i n a l c o n c e n t r a t i o n a f t e r two y e a r s , and s i x p e r c e n t a f t e r t h r e e y e a r s . P i c l o r a m r e s i d u e s w e re m o s t o f t e n c o n c e n t r a t e d i n t h e u p p e r 15 .2 cm o f s o i l . S c i f r e s e t a l . (1 971 ) r e p o r t e d t h a t p i c lo r am (0.28 k g /h a ) d i s s i p a t e d w i t h i n one y e a r , and 42 u s u a l l y w i t h i n 90 d a y s when a p p l i e d t o s e m i a r i d r a n g e l a n d i n w e s t T exas . V a r i a t i o n i n t h e r e s i d u a l a c t i v i t y o f p i c lo r am . i s a t t r i b u t e d to d i f f e r e n c e s i n s o i l p r o p e r t i e s , e l e v a t i o n , c l i m a t e , a nd i n i t i a l h e r b i c i d e c o n c e n t r a t i o n s . P i c l o r a m i s m ore p e r s i s t e n t i n c l a y o r sandy loam th an sandy t e x t u r e d s o i l s ( 'Herr e t a l . I ‘966 : M erke l e t a l . , 1967). The r a p i d d i s s i p a t i o n i n l i g h t t e x t u r e d s o i l s may be due to l e a c h i n g ( B u r n s i d e e t a l . , 1 971 j M e rk e l e t a l . , 1967 ) s i n c e t h e p e r c e n t c l a y f r a c t i o n , h ad no s i g n i f i c a n t i n f l u e n c e on t h e r a t e o f p i c l o r am d e c om p o s i t io n (Youngson e t a l . , 1967). P ic lo r am d e c om p o s i t io n r a t e s a r e i n c r e a s e d a s s o i l o r g a n i c m a t t e r c o n t e n t a n d t e m p e r a t u r e i n c r e a s e s (H u n t e r a n d S t o b b e , 1 972 ; Y oungson e t a l . , 1967 ; G r o v e r , 1968; M erk le e t a l . , 1967). The r a t e o f d e c om p o s i t io n ■ d e c r e a s e s w i t h i n c r e a s i n g d e p t h i n t h e s o i l p r o f i l e (H u n t e r and S t o b b e , 1 9 72 ) , a n d d e c r e a s i n g l e v e l s o f s o i l m o is tu r e (Youngson e t a l . , 1967). U l t r a v i o l e t l i g h t decomposes p i c l o r am on p l a n t and s o i l s u r f a c e s ( H a l l e t a l . , 1 968 ; M e rk le e t a l . , 1 9 6 7 ) . P h o t o l y t i c d e g r a d a t i o n o f p i c l o r am i s g r e a t e s t a t h ig h e l e v a t i o n s s in c e s o l a r r a d i a t i o n i n c r e a s e s w i t h a l t i t u d e (Johnson and M a r t in , 1983). Once i n t h e s o i l , p i c lo r am i s p r o t e c t e d f rom p h o to -d e c om p o s i t io n . The r a t e o f . p i c l o r a m d i s s i p a t i o n i s a l s o r e l a t e d to i n i t i a l h e r b i c i d e c o n c e n t r a t i o n . H un te r and S tobbe (1972) d e te rm in e d t h a t th e p e r c e n t o f p i c l o r a m d e g r a d e d w as g r e a t e r a t l o w e r d o s e s . T h i s i n d i c a t e s t h a t a l a g p e r i o d o c c u r s i n p ic lo r am d e g r a d a t i o n when h ig h c o n c e n t r a t i o n s a r e a p p l i e d (G rover , 1967). 43 S p o t t e d Knapweed Response to 2 ,4 -D S p o t te d knapweed c o n t r o l w i t h 2,4-D ( (2 ,4 - d ic h lo ro -p h e n o x y ) a c e t i c a c i d ) i s e x t r e m e l y v a r i a b l e , C h i c o i n e (1 9 84 ) f o u n d t h a t t h e p e r c e n t c o n t r o l o f s p o t t e d k n apw eed a f t e r one y e a r w i t h 2 .24 k g / h a o f 2 ,4 -D am ine r a n g e d from 21 t o 100 p e r c e n t a t two l o c a t i o n s . R e s u l t s i n Idaho w e re s i m i l a r w i t h s p o t t e d k n apw eed c o n t r o l r a n g i n g f rom 30 t o 84 p e r c e n t w i t h 1 .12 k g /h a o f 2 ,4-D ( B e l l e s e t a l . , 1978; W a tte n b a rg e r e t a l . , 1 9 8 0 ) . C r a n s t o n (1 9 8 4 ) r e p o r t e d t h a t e f f e c t i v e c o n t r o l o f s e e d l i n g s was o b t a i n e d w i t h 2 ,4 -D , however , r o s e t t e p l a n t s r e c o v e r e d f r om t h e h e r b i c i d e . Re t r e a t m e n t o f 2 ,4 -D i s n e c e s s a r y t o g a i n a c c e p t a b l e l e v e l s o f c o n t r o l o f m a tu re s p o t t e d knapweed p l a n t s (Maddox, 1979). V a r i a t i o n i n c o n t r o l o f s p o t t e d knapweed w i t h 2,4-D may be due t o e n v i r o n m e n t a l c o n d i t i o n s o r d i f f e r e n c e s i n t o l e r a n c e w i t h i n t h e s p e c i e s . D i f f e r e n t i a l t o l e r a n c e to 2 ,4-D w i t h i n weed s p e c i e s h a s long been r e c o g n iz e d . McCall (1954) and H i l t o n (1957) i d e n t i f i e d two s t r a i n s o f C om m e l in a d i f f u s a h a v i n g d i f f e r e n t i a l t o l e r a n c e t o 2 ,4 -D a s e a r l y a s 1950. One s t r a i n was e a s i l y c o n t r o l l e d w i th 2 ,4-D a t 1 .12 k g /h a w h i le 5 .6 k g / h a w e re r e q u i r e d t o c o n t r o l t h e o t h e r . W h i tw o r t h (1 9 6 4 ) r e p o r t e d d i f f e r e n c e s i n r e s p o n s e to 2 ,4 -D by s t r a i n s o f f i e l d b indweed ( C o n v o l v u l u s a r v e n s i s ) . S e x s m i t h (1 9 6 4 ) f o u n d d i f f e r e n c e s among 12 s t r a i n s o f w h i t e t o p (C a r d a r i a c h a l e p e n s i s ) i n r e s p o n s e to 2 ,4-D. There h av e a l s o b e e n r e p o r t s o f v a r i a t i o n i n s e n s i t i v i t y t o 2 ,4 -D w i t h i n c o l l e c t i o n s o f k o ch ia (Kochia s c o p a r i a ) (B e l l e t a l . , 1972). D i f f e r e n t i a l r e s p o n s e t o a h e r b i c i d e w i t h i n a s p e c i e s o f t e n depends on f a c t o r s t h a t i n f l u e n c e th e amoun t o f h e r b i c i d e , r e a c h in g th e 44 p h y t o t o x i c s i t e o f a c t i o n . T h i s i n c l u d e s d i f f e r e n c e s i n u p t a k e , t r a n s l o c a t i o n , a n d m e t a b o l i s m o f t h e h e r b i c i d e . The u p t a k e o f a h e r b i c i d e can be i n f l u e n c e d by g row th h a b i t , c u t i c l e c om p o s i t io n and t h i c k n e s s , o r l e a f s u r f a c e p u b e s c e n c e . H odgson (1 9 7 3 ) r e p o r t e d t h a t v a r i a t i o n i n c u t i c l e t h i c k n e s s among Canada t h i s t l e ( C ir s ium a r v e n s e ) e c o t y p e s m o d i f i e d t h e i r r e s p o n s e t o 2 , 4 -D . H u l l (1 9 6 4 ) r e p o r t e d a n i n v e r s e c o r r e l a t i o n b e tw e e n c u t i c l e t h i c k n e s s and a c t i v i t y o f 2 ,4-D. I n c r e a s i n g t h i c k n e s s o f i s o l a t e d c u t i c l e w i t h i n a s p e c i e s h a s b e e n shown t o r e d u c e 2 , 4 -D p e n e t r a t i o n ( S k o s s , 1 9 5 5 ) . N o r r i s (1 9 7 4 ) r e p o r t e d t h a t t h e q u a l i t y and q u a n t i t y o f wax were more im p o r t a n t t h a n t h i c k n e s s i n d e t e rm in in g p e n e t r a t i o n .o f 2 ,4-D. T r a n s l o c a t i o n o f 2 ,4-D i s m o s t ly s y m p l a s t i c w i t h t r a n s p o r t o f t h e h e r b i c i d e t o a c t i v e m e t a b o l i c s i t e s . L ack o f p h lo em t r a n s p o r t i s a n im p o r t a n t mechanism i n d e t e rm in in g d i f f e r e n t i a l s e n s i t i v i t y to 2 , 4 -D among p l a n t s p e c i e s ( J e n so n , 1982). M e t a b o l i sm o f 2 , 4-D t o a n i n a c t i v e f o rm i s a n o t h e r f a c t o r r e g u l a t i n g s e n s i t i v i t y t o a h e r b i c i d e . D e t o x i f i c a t i o n o f 2 , 4-D c a n o c c u r b y : (1 ) s i d e - c h a i n d e c a r b o x y l a t i o n , (2 ) s u g a r c o n j u g a t i o n , (3 ) c o n ju g a t i o n w i t h g lu tam in e and a s p a r t a t e " , a n d (4 ) r i n g h y d r o x y l a t i o n (M u l l i s o n , 1982) (F ig u r e 5 ). L u c k w i l l a n d L l o y d - J o n e s (1 9 6 0 ) f o u n d t h a t t h e a b i l i t y t o d e c a r b o x y la t e 2 , 4-D v a r i e d w id e ly b e tw e e n v a r i e t i e s o f a p p l e s (P y r u s s p . ) a n d s t r a w b e r r y ( F r a g a r i a s p . ) . T o l e r a n t v a r i e t i e s c o u l d d e c a r b o x y l a t e 59 p e r c e n t o f a b s o r b e d 14C 2 , 4-D c om p a r e d t o o n l y 2 p e r c e n t i n a s e n s i t i v e v a r i e t y . However, i n h e r e n t t o l e r a n c e to 2 ,4-D a p p e a r s to be more complex th an d e c a r b o x y l a t i o n a lo n e . L u c kw i l l and 45 L lo y d - J ones (1960) showed d a ta from 17 s p e c i e s i n which t h e r e was no a s s o c i a t i o n b e tw een t o l e r a n c e and d e c a r b o x y la t i o n o f 2 ,4-D. R = Amino AcidsOCH7C-R Ring HyUroxyIaiion ? H Amino Acid ConjugationChain Oxidation Cl OH Amino Acid Conjugation OCH7COOH Rmq Hydroxylaf-on WH 2,5 D\ 40H 2,3 0 SOU 2,4 D 60H 2 4 D 30H-2.4 D 40H-2 Cl 1 Sugar I Conjugation 20H 4-CI /CCH2C O Suijdr F i g u r e 5. Summary o f 2 ,4 -D M e ta b o l i sm by P l a n t s ( f r o m Feung e t a l . , 1978) . W h i tw o r t h and M uz ik ( I 967 ) r e p o r t e d t h a t d i f f e r e n t i a l r e s p o n s e w i t h i n f i e l d b in d w e e d was n o t r e l a t e d t o d i f f e r e n c e s i n l e a f m o rp h o lo g y , p l a n t v i g o r , o r a d s o r p t i o n and t r a n s l o c a t i o n o f t h e h e r b i c i d e . The d i f f e r e n t i a l r e s p o n s e a p p e a r e d t o b e t h r o u g h d e a c t i v a t i o n o f 2 ,4-D w i t h in c e l l s o f th e t o l e r a n t t i s s u e by b in d in g to n o n a c t i v e s i t e s . A d so rp t io n to n o n a c t i v e s i t e s h a s a l s o been p ropo sed a s t h e m ec h a n ism o f t o l e r a n c e w i t h i n w i l d c a r r o t (C a u c u s c a r o t a ) (W h itehead and S w i t z e r , 1963). 46 I n g e n e r a l , i t a p p e a r s t h a t d i f f e r e n t i a l r e s p o n s e to 2 ,4-D w i t h in a p l a n t s p e c i e s i s b a sed more on i n t e r n a l p h y s i o l o g i c a l f a c t o r s r a t h e r th an m o rp h o lo g ic a l c h a r a c t e r i s t i c s . Rapid h e r b i c i d e m e tab o l i sm and i t s e f f e c t on t r a n s l o c a t i o n a r e o f t e n im p l i c a t e d when t o l e r a n c e w i t h in a s p e c i e s i s n o t e d . The d eg re e o f t o l e r a n c e w i t h in a s p e c i e s a p p e a r s to be h e r i t a b l e ( J e n s e n , 1982). Summary S p o t t e d k n apw eed i s a n a g g r e s s i v e , i n t r o d u c e d weed t h a t h a s in v ad ed ove r 800 ,000 h e c t a r e s o f g r a z e a b l e w o o d la n d a n d r a n g e l a n d i n M o n ta n a . A b o u t 1 3 .8 m i l l i o n h e c t a r e s a r e h i g h l y s u s c e p t i b l e t o i n v a s i o n by s p o t t e d knapweed i n th e s t a t e . S p o t t e d k n a pw e ed i s w e l l a d a p t e d a n d r e p r o d u c e s e f f e c t i v e l y by s e e d . I n d i v i d u a l p l a n t s c a n p r o d u c e f rom 436 t o 2 5 ,2 6 3 s e e d s u n d e r d r y l a n d and i r r i g a t e d c o n d i t i o n s r e s p e c t i v e l y . While t h e e x a c t p e r i o d o f l o n g e v i t y o f v i a b i l i t y o f s p o t t e d knapweed seed i n t h e s o i l h a s n o t been d e te rm in e d , i t h a s been found to exceed f i v e y e a r s . S p o t t e d k n apw eed c a n e s t a b l i s h a n d t h r i v e u n d e r a w id e r a n g e o f e n v i r o n m en ta l c o n d i t i o n s . Once e s t a b l i s h e d , s p o t t e d knapweed s p r e a d s r a p i d l y . The p r e s e n c e o f an a l l e l o p a t h i c c h em ic a l w i t h i n th e l e a v e s o f s p o t t e d k n apw eed s u p p r e s s e s t h e g r o w t h o f s u r r o u n d i n g v e g e t a t i o n . G ra ss p r o d u c t i o n can be r e d u c ed 80 to 90 p e r c e n t by i n v a s i o n o f s p o t t e d knapweed. P ic lo r am i s t h e m o s t e f f e c t i v e h e r b i c i d e f o r c o n t r o l l i n g s p o t t e d k n a pw e e d . One a p p l i c a t i o n o f 0 .28 k g / h a o f p i c l o r a m c a n c o n t r o l s p o t t e d knapweed f o r one to f i v e y e a r s . The. p e r s i s t e n c e o f p i c lo r am i n 47 s o i l d e t e r m i n e s t h e l e n g t h o f c o n t r o l o f a a g i v e n weed s p e c i e s . The r e s i d u a l a c t i v i t y o f p i c l o r a m w i l l v a r y a c c o r d i n g t o t e m p e r a t u r e , C ' r a i n f a l l , s o i l p r o p e r t i e s s u c h a s p e r c e n t c l a y a n d o r g a n i c m a t t e r , e l e v a t i o n , and i n i t i a l r a t e o f h e r b i c i d e a p p l i e d . S p o t t e d k n apw eed c o n t r o l w i t h 2 ,4 -D i s e x t r e m e l y v a r i a b l e . V a r i a t i o n i n c o n t r o l b e tw e e n s i t e s may be due t o e n v i r o n m e n t a l d i f f e r e n c e s , o r i n h e r e n t t o l e r a n c e w i t h i n s t r a i n s o f s p o t t e d knapweed. M o r p h o l o g i c a l a n d p h y s i o l o g i c a l d i f f e r e n c e s w i t h i n a s p e c i e s c an i n f l u e n c e u p ta k e , t r a n s l o c a t i o n , and m e tab o l ism o f t h e h e r b i c i d e 48 CHAPTER 5 THE EFFECT OF REDUCED RATES OF PICLORAM ON THE LONGEVITY OF CONTROL OF SPOTTED KNAPWEED A b s t r a c t S p o t t e d knapweed (C en tau rea m acu lo sa Lam.) c o n t r o l w i t h p i c lo r am a n d p i c l o r a m / 2 , 4 - D c o m b i n a t i o n s was m e a s u r e d a t tw o l o c a t i o n s i n Montana. P ic lo r am was a p p l i e d a t r a t e s r a n g in g from 0.07 to 0.28 k g /h a a lo n e and i n c om b in a t io n w i th 2.24 k g /h a o f 2 ,4-D . R e s u l t s showed t h a t a l l r a t e s o f p i c l o r am s i g n i f i c a n t l y r e d u c ed m a tu re and s e e d l i n g s p o t t e d k n a pw e e d d e n s i t i e s 26 m o n th s f o l l o w i n g h e r b i c i d e a p p l i c a t i o n . The a d d i t i o n o f 2 ,4 -D t o 0 .0 7 k g / h a o f p i c l o r a m s i g n i f i c a n t l y r e d u c e d s p o t t e d k n a pw e ed d e n s i t y when c om p a r e d t o 0 .07 k g / h a o f p i c l o r a m a p p l i e d a l o n e . F o r a g e p r o d u c t i o n i n c r e a s e d 200 t o 770 p e r c e n t i n r e s p o n s e to th e r e d u c t i o n i n s p o t t e d knapweed d e n s i t y . S o i l b i o a s s a y s c l e a r l y i n d i c a t e d t h a t p e r s i s t e n c e o f . p i c lo r am i n s o i l i s an im p o r t a n t f a c t o r i n m a in t a i n in g lo n g - t e rm c o n t r o l o f s p o t t e d knapweed. I n t r o d u c t i o n S p o t t e d k n apw eed ( C e n t a u r e a m a c u lo s a Lam.) i s a s h o r t l i v e d p e r e n n i a l weed w h ic h i n f e s t s m ore t h a n 8 0 0 ,0 0 0 ha o f r a n g e a n d p a s t u r e l a n d i n M on tan a (M addox , 1 9 7 9 ) . The p l a n t r e p r o d u c e s by s e e d a n d s p r e a d s r a p i d l y due t o a n a l l e l o p a t h i c e f f e c t on s u r r o u n d in g - v e g e t a t i o n ( F l e t c h e r a n d R enney , 1 9 6 3 ) . C a r r y i n g c a p a c i t y can. be 49 r e d u c e d 80 t o 90 p e r c e n t by i n v a s i o n o f s p o t t e d k n apw eed ( C h i c o i n e , 1984J Watson and Renney, 1974). H e r b i c i d e s a r e t h e m o s t e f f e c t i v e m eans o f c o n t r o l l i n g s p o t t e d knapweed. P ic lo r am a t 0.28 k g /h a h a s been shown to p r o v id e from one to f i v e y e a r s o f c o n t r o l o f s p o t t e d k n apw eed ( C h i c o i n e , 1 984 ; C r a n s t o n , 1 9 8 4 ) . I t h a s b e e n s u g g e s t e d t h a t t h e l e n g t h o f c o n t r o l i s d e p e n d e n t e i t h e r on p i c l o r am r e s i d u e s r em a in in g i n th e s o i l o r f rom c o m p e t i t i o n f rom a s s o c i a t e d s p e c i e s (C h ico in e , 1984; H a r r i s and C r a n s to n , . 1979). L e n g th o f c o n t r o l f r om p i c l o r a m r a t e s b e lo w 0 .28 k g / h a h a s n o t b een d e te rm in e d . The optimum r a t e o f h e r b i c i d e needed to c o n t r o l t h i s weed m u s t be d e te rm in e d b ecau se o f e c o l o g i c a l and econom ic c o n c e rn s f o r r a n g e l a n d . The o b j e c t i v e s o f t h i s s t u d y w e r e : (1 ) To d e t e r m i n e t h e o p t im um h e r b i c i d e r a t e o f p i c l o r am and p i c l o r a m /2 , 4 ~ D c o m b i n a t i o n s n e e d e d t o c o n t r o l s p o t t e d k n a pw e e d , (2 ) t o m e a s u r e t h e g r o w t h r e s p o n s e o f a s s o c i a t e d v e g e t a t i o n a f t e r r e m o v a l o f s p o t t e d k n a pw e e d , and (3 ) t o m e a s u r e t h e p e r s i s t e n c e o f low r a t e s o f p i c l o r a m u n d e r r a n g e l a n d c o n d i t i o n s i n Montana. M a t e r i a l s and Methods P ic lo r am Rate S tudy F i e l d t r i a l s w e re e s t a b l i s h e d i n J u n e , 1982 by T im o th y K. C h ic o in e , f o rm e r r e s e a r c h a s s i s t a n t , P l a n t and S o i l S c ie n c e D epa r tm en t , Montana S t a t e U n iv e r s i t y . Three s i t e s were o r i g i n a l l y s e l e c t e d f o r t h e s t u d y h o w e v e r , t h e s i t e n e a r S t e v e n s v i l l e , M on tan a w as d e s t r o y e d by b u i l d i n g c o n s t r u c t i o n i n 1983 . The s i t e c h a r a c t e r i s t i c s o f t h e r em a in in g two l o c a t i o n s a r e d e s c r i b e d . f i 50 S i t e 1 was l o c a t e d n e a r O vando , M on tana on t h e B l a c k f o o t - C l e a rw a t e r Game Refuge. The s tu d y was e s t a b l i s h e d on g e n t l y r o l l i n g f o o t h i l l s c h a r a c t e r i z e d by a g r a s s l a n d community ty p e . The s i t e was d o m in a t e d by t im o t h y (P h leum p r a t e n s e ) * sm o o th b r .om eg r a s s (B ro mu s i n e r m i s ) , a n d K e n tu c k y b l u e g r a s s (Ppa p r a t e n s i s ) . The d o m in a n t f o r b was s p o t t e d knapweed. A d e t a i l e d d e s c r i p t i o n o f th e p l a n t community i s shown i n Appendix D (Tab le 35').' The s i t e had been c u l t i v a t e d i n 1954 and se ed ed to t im o th y . There was no g r a z i n g use on th e s tu d y l o c a t i o n by e i t h e r d om e s t ic a n im a l s o r w i l d l i f e d u r in g th e two y e a r s tu d y p e r i o d (Dan N ea l , 1985, p e r s o n a l com m un ica t ion ) . The e l e v a t i o n a t t h e s t u d y s i t e was 1837 m a n d a v e r a g e a n n u a l p r e c i p i t a t i o n d u r in g th e two y e a r s tu d y p e r i o d was 40 cm (Appendix D, Tab le 36). The s o i l s were c l a s s i f i e d a s l o a m y - s k e l e t a l , m ixed, f r i g i d T y p i c H a p l u s t o l s ( A p p e n d i x D, T a b l e 3 8 ) . S i t e 2 was l o c a t e d a p p r o x im a t e l y 15 m i l e s s o u t h o f H a r l o w to n , Montana on a f l o o d p l a i n . The s i t e c o n s i s t e d o f a g r a s s l a n d v e g e t a t i o n community d om in a te d by w e s t e r n w h e a tg ra s s (Agropyron s m i t h i i ) , Kentucky b l u e g r a s s (Poa p r a t e n s i s ) , n e e d l e - a n d - t h r e a d ( S t i p a c o m a t a ) , a n d b l u e grama (B ou te lo u a g r a c i l i s ). S p o t te d knapweed was th e d om in an t f o r b . A d e t a i l e d d e s c r i p t i o n o f t h e p l a n t c om m un i ty i s shown i n A ppend ix D ( T a b l e 35 ) . The s t u d y a r e a was l o c a t e d w i t h i n a 245 h e c t a r e p a s t u r e t h a t was s to c k e d e a c h y e a r w i th 700 a n im a l u n i t s from November t h ro u g h May. A l though s u p p lem en ta l f e e d was p r o v id e d , th e a r e a r e c e iv e d heavy g r a z i n g p r e s s u r e d u r i n g t h e e a r l y s p r i n g m o n th s ( B i l l J o n e s , 1985 , p e r s o n a l com m un ica t ion ) . I : 51 The e l e v a t i o n a t t h e s i t e w a s 2041 m a n d a v e r a g e a n n u a l p r e c i p i t a t i o n was 37 cm d u r in g th e s tu d y p e r i o d (Appendix D, Tab le 36'). The s o i l was c l a s s i f i e d a s a l o a m y - s k e l e t a l , m ix e d , f r i g i d U s t i c T o r r i f l u v e n t (Appendix D, T ab le 39l). The t h i c k n e s s o f th e s u r f a c e s o i l l a y e r r a n g e d f r o m 5 t o 20 cm. T r i a l s w e r e a r r a n g e d i n a s p l i t b l o c k d e s i g n w i t h t h r e e r e p l i c a t i o n s p e r t r e a tm e n t . P ic lo r am was' th e main p l o t t r e a tm e n t and was a p p l i e d a t r a t e s o f 0 .0 , 0 .0 7 , 0 .1 1 , 0 .1 4 , 0 .2 1 , 0 .2 2 , 0 .2 5 , a n d 0 .2 8 kg a . i , . / h a . The s u b p l o t t r e a t m e n t was 2 ,4 -D a p p l i e d a t t h e r a t e o f 2 .24 kg a . i . / h a . F u r t h e r d e t a i l s c o n c e r n i n g t h e p l o t d e s i g n a n d h e r b i c i d e a p p l i c a t i o n were d e s c r i b e d by C h ico in e (1984). M atu re and s e e d l i n g s p o t t e d knapweed d e n s i t y c o u n t s a n d ' b iom ass m ea su rem en ts were t a k e n i n J u ly , 1984. Two q u a r t e r m e te r sq u a re f r am e s w e re p l a c e d a t r andom l o c a t i o n s w i t h i n e a c h s u b p l o t . M a tu r e a n d i s e e d l i n g s p o t t e d k n apw eed d e n s i t y c o u n t s w e re made i n e a c h f r a m e . ;| V e g e ta t io n w i t h in t h e f ram e was c l i p p e d a t g round l e v e l and th e c u r r e n t y e a r s g row th s e p a r a t e d i n t o p e r e n n i a l g r a s s e s , a n n u a l g r a s s e s , f o r b s , s h ru b s , ■ and s p o t t e d knapweed. The v e g e t a t i o n was oven d r i e d a t 50 C / f o r 48 hours' to d e te rm in e d ry w e ig h t . The number o f o t h e r f o r b s p e c i e s p r e s e n t i n e a c h t r e a t m e n t w as d e t e r m i n e d i n J u n e , 1984« T h re e 0 .0 9 i sq u a re m e te r f r am e s were random ly p l a c e d w i t h in e a ch s u b p lo t and t h e | number o f f o r b s p e c i e s r e c o rd e d . ; D a ta c o l l e c t e d may h av e b e e n b i a s e d by e a r l i e r f i e l d t e c h n i q u e s s i n c e p l o t s c l i p p e d i n 1982 a n d 1983 w e re n o t p e rm a n e n t l y m a rk ed o r ! l o c a t e d a lo n g e s t a b l i s h e d t r a n s e c t s . A l though an a t t e m p t was made to a v o i d t h e s e a r e a s w h i l e c o l l e c t i n g 1 9 8 4 d e n s i t y a n d b i o m a s s ' 53 The am o u n t o f p i c l o r a m r e m a i n i n g i n t h e s o i l was d e t e r m i n e d by b io a s s a y . I n p r e p a r a t i o n f o r th e b i o a s s a y , 300 g ram s o f s o i l f rom ea ch p i c l o r a m t r e a t m e n t a n d t h e u n t r e a t e d c o n t r o l was p l a c e d i n 10 cm d i a m e t e r by 7 cm d e e p s t y r o f o a m c u p s . F i e l d b e a n s (P h a s e o l u s v u l g a r i s ) and s p o t t e d knapweed were u sed a s b io a s s a y i n d i c a t o r p l a n t s . F iv e b e an s and 10 s p o t t e d knapweed s e e d s were p l a c e d i n e a ch p o t . The p o t s w e re a r r a n g e d a s a r a n d o m i z e d c o m p l e t e b l o c k d e s i g n w i t h t h r e e r e p l i c a t i o n s p e r t r e a tm e n t . There were two p o t s i n e a ch r e p l i c a t i o n which s e rv e d a s s u b sam p le s . P l a n t s w e re g row n i n t h e g r e e n h o u s e a t 16 C n i g h t a n d 21 C d ay t em p e r a t u r e s . S u p p lem en ta l f l u o r e s c e n t l i g h t w as p r o v i d e d t o e x t e n d th e p h o to p e r io d to 16 h ou rs p e r day. P o t s were weighed t h r e e t im e s p e r w eek a n d w a t e r a d d e d t o m a i n t a i n s o i l m o i s t u r e a t f i e l d c a p a c i t y . A f t e r one week, th e p l a n t s were t h in n e d to t h r e e b e an s and f i v e s p o t t e d k n a pw e ed p e r p o t and g row n f o r a n a d d i t i o n a l t h r e e w e ek s . The b e a n s w e re h a r v e s t e d one m o n th a f t e r p l a n t i n g a n d o v en d r i e d a t 50 C f o r 48 h o u r s . D ry w e i g h t s o f t h e f i r s t tw o t r u e l e a v e s w e re m e a s u r e d . S p o t t e d k n a pw e ed s e e d l i n g s w e re g row n f o r a n a d d i t i o n a l m o n th , h a r v e s t e d , a n d t h e o v en d r y w e i g h t o f t h e s e e d l i n g s w as a v e r a g e d f o r e a ch p o t . The e x p e r im e n t was conduc ted tw ic e . S ta n d a rd r e f e r e n c e c u rv e s were p r e p a r e d u s in g u n t r e a t e d s o i l f rom b o t h l o c a t i o n s . To d e t e r m i n e t h e am o u n t o f p i c l o r a m n e c e s s a r y t o c o n s t r u c t t h e s t a n d a r d s , i t was a s s u m e d t h a t 7*6 cm o f s o i l f rom an a r e a o f one h e c t a r e w e ig h e d 1.1 m i l l i o n kg . From t h i s a s s u m p t i o n , a 0.28 k g /h a a p p l i c a t i o n o f p i c lo r am was e q u i v a l e n t to a p p ro x im a te ly 256 ppbw 54 S ta n d a rd s were p r e p a r e d by a d d in g 300 g ram s o f u n t r e a t e d s o i l to s ty ro fo am p o t s . S o l u t i o n s o f p i c l o r am were added to th e u n t r e a t e d s o i l a t c o n c e n t r a t i o n s o f 0 , 0 .5 , 1 , 2 , 4 , 8 , 16 , 3 2 , 64 , 128 , a n d 256 p a r t s p e r b i l l i o n by w e i g h t (p p bw ) . The h e r b i c i d e w as a l l o w e d t o e q u i l i b r a t e i n t h e s o i l f o r one week b e f o r e p l a n t i n g . F i e l d b e a n s and s p o t t e d knapweed were u sed a s b io a s s a y ' p l a n t s and grown unde r i ■ th e same c o n d i t i o n s a s d e s c r i b e d above f o r th e f i e l d s am p le s . S im p l e . l i n e a r r e g r e s s i o n a n a l y s i s , I = a + bx ( w he re a= Y i n t e r c e p t a n d b= s l o p e ) , was u s e d t o a n a l y z e t h e e f f e c t o f p i c l o r a m c o n c e n t r a t i o n s ( i n d e p e n d e n t v a r i a b l e , X) on t h e w e i g h t o f t h e b e a n l e a v e s (d ep end en t v a r i a b l e , Y) (F ig u re 5 ) . The r e g r e s s i o n was used to d e t e rm in e th e amoun t o f p i c lo r am r em a in in g i n th e f i e l d s am p le s . An a n a l y s i s o f v a r i a n c e was u s e d t o t e s t f o r d i f f e r e n c e s b e tw e e n t r e a tm e n t s . R e s u l t s and D i s c u s s io n P ic lo r am Ra te S tudy A l I r a t e s o f p i c l o r a m a n d p i c l o r a m / 2 , 4 -D c o m b i n a t i o n s s i g n i f i c a n t l y r e d u c ed m a tu re and s e e d l i n g s p o t t e d knapweed d e n s i t y 26 months a f t e r h e r b i c i d e a p p l i c a t i o n (T ab le 15 and 16). P ic lo r am a lo n e a t r a t e s f r om 0 .14 t o 0 .28 k g / h a c o n t i n u e d t o p r o v i d e 100 p e r c e n t c o n t r o l o f m a t u r e s p o t t e d k n apw eed 2,6 m o n th s f o l i o w ing h e r b i c i d e a p p l i c a t i o n . Complete c o n t r o l o f m a tu re s p o t t e d knapweed p l a n t s was n o t o b t a i n e d a t p i c lo r am r a t e s be low 0.14 k g /h a a lo n e o r i n c om b in a t io n w i th 2 , 4 -D . M a tu r e s p o t t e d k n apw eed d e n s i t i e s d e c r e a s e d f rom 35.7 p l a n t s i n 1982 t o 9 .0 p l a n t s p e r q u a r t e r m e t e r s q u a r e i n 1 984 on p l o t s t r e a t e d LU - I >- P 6 0 DC Z Q O < Li. LU O LOG PICLORAM CONCENTRATION F ig u re 6. The S ta n d a rd Curve Used f o r th e P ic lo ram B io a ssay . P o i n t s on th e R e g re s s io n I n d i c a t e th e Dry Weight o f Bean Leaves a s a P e r c e n t o f th e C on t ro l f o r e a ch P ic lo ram C o n c e n t r a t io n . 56 Tab le 15. Number o f Mature S p o t te d Knapweed P l a n t s p e r 0.25 m2 i n J u l y 1983 and J u l y 1984 , 14 and 26 M on th s A f t e r P i c l o r a m A p p l i c a t i o n a t H a r low ton and OvandoJ J u l y 1983 J u ly II g Har low ton Ovando Har low ton Ovando P ic lo r am 2,4--D am ine 2 , 4-D am ine 2 , 4-D am ine 2 , 4-D am ine r a t e r a t e kg /h a r a t e kg /h a r a t e kg /h a r a t e kg /h a ( k g / ha ) 0 .00 2 .24 0 .00 2 .24 0 .00 2 .24 0 .00 2 .24 0 .28 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .25 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .22 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0.21 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .14 0 .0 0 .0 0 .0 0 .0 0.0 0 .0 0 .0 0 .0 0.11 0 .0 0 .0 0 .5 0 .3 0 .0 0 .2 0 .5 0 .0 0 .07 0 .4 0 .0 35 .7 0.1 0 .7 0 .0 9.0 0 .8 0 .00 42.1 0 .0 25 .9 19.1 37 .7 1 .7 41 .8 41 .3 LSD. 05 0.7 21.7 0.8 5 .2 1 P i c l o r a m r a t e s w e re a p p l i e d a l o n e and i n c o m b i n a t i o n w i t h 2 ,4 -D on June 16 and 17,, 1982. T ab le 16. Number o f i n J u ly 1983 A p p l i c a t i o n < Imm atu re S p o t t e d Knapweed P l a n t s p e r and J u l y 1984» 14 and 26 Months A f t e r a t H a r low ton and OvandoJ 0.25 m2 P ic lo r am J u ly 1983 H a r low ton Ovando J u l y 1984 H a r low ton Ovando P ic lo r am 2 ,4-D am ine 2 , 4-D am ine 2 , 4-D am ine 2 ,4 - D am ine r a t e r a t e kg /h a r a t e kg /h a r a t e kg /h a r a t e kg /h a (kg /h a ) 0.00 2.24 0 .00 2 .24 0.00 2 .24 0 .00 2 .24 0 .28 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .25 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .22 0 .0 0 .0 0 .0 0 .0 0.0 0 .0 0.0 0 .0 0.21 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .0 0 .14 0.1 0 .0 0.1 0 .0 0.0 0 .2 0.5 0 .0 0.11 0 .5 0.1 0 .2 0.1 0 .0 0 .2 0 .7 0 .0 0 .07 0 .4 0 .0 48 .5 0.1 1.0 0 .0 3 .2 1 .0 0 .00 725 .0 2 .4 510 .0 47.1 638 .5 2 .5 526 .5 552 .0 LSD. 05 89.9 206.2 98 .6 66 .4 ^P i c l o r a m r a t e s w e re a p p l i e d a l o n e a n d i n c o m b i n a t i o n w i t h 2 , 4-D on J u n e 16 a n d 17» 1982 . 57 w i t h 0 .07 k g / h a p i c l o r a m a t Ovando . M a tu r e s p o t t e d k n apw eed p l a n t s g row in g on t h e s e p l o t s i n 1983 e x h i b i t e d p i c lo r am symptoms ( e p in a sy and r e d u c e d b i o m a s s ) ( C h i c o i n e , 1 9 8 4 ) . The d e c r e a s e i n s p o t t e d k n apw eed d e n s i t y from 1983 to 1984 was e i t h e r t h e r e s u l t o f p i c l o r am r e s i d u e s i n t h e s o i l a n d / o r w i n t e r k i l l due t o r e d u c e d v i g o r o f t h e p l a n t s . The u se o f 0.07 and 0.11 k g /h a o f p i c l o r am i s n o t e f f e c t i v e s in c e c om p le te c o n t r o l o f m a tu re s p o t t e d knapweed p l a n t s was n o t o b t a i n e d . R e in v a s io n by s p o t t e d knapweed s e e d l i n g s o c c u r r e d i n b o th 1983 and 1984 on p l o t s t r e a t e d w i t h l e s s t h a n 0.21 k g / h a o f p i c l o r a m (T a b l e 16). A l th ough th e number o f s p o t t e d knapweed s e e d l i n g s i n th e t r e a t e d p l o t s was n o t s i g n i f i c a n t , i t i s an im p o r t a n t f a c t o r i n d e t e rm in in g th e l e n g t h o f c o n t r o l o f t h e weed on r a n g e l a n d . P r e v i o u s s t u d i e s h av e shown t h a t once s e e d l i n g e s t a b l i s h m e n t b e g in s , c om p le te r e i n f e s t a t i o n o c c u r s r a p i d l y ( C h i c o i n e , 1 9 8 4 ) . Low s e e d l i n g e s t a b l i s h m e n t i n p i c l o r am t r e a t e d p l o t s i s th e r e s u l t o f e i t h e r p i c l o r am r e s i d u e s i n t h e s o i l , r e d u c e d s e e d l i n g v i g o r (d u e t o a g i n g o f t h e s e e d ) ^ a n d / o r c o m p e t i t i o n from p e r e n n i a l g r a s s s p e c i e s . The a d d i t i o n o f 2 ,4 -D w i t h 0 .0 7 k g / h a o f p i c l o r a m s i g n i f i c a n t l y r e d u c e d s p o t t e d k n a pw e ed d e n s i t y c o m p a r e d t o 0 .07 k g / h a o f p i c l o r a m a l o n e a t Ovando , h o w e v e r , t h i s r e l a t i o n s h i p . w as n o t o b s e r v e d a t H a r lo wton. P ic lo r am a lo n e a t r a t e s above 0.07 k g /h a p ro v id e d th e same c o n t r o l o f s p o t t e d knapweed a s p i c l o r am i n c om b in a t io n w i t h 2,4~D. The a p p l i c a t i o n o f 2 , '4 -D a l o n e s i g n i f i c a n t l y r e d u c e d m a tu r e s p o t t e d knapweed d e n s i t i e s a t H a r lo wton, b u t had no e f f e c t on p l a n t d e n s i t y a t Ovando i n e i t h e r 1983 o r 1984 (T ab le 15). 58 P e r e n n i a l g r a s s p r o d u c t i o n i n c r e a s e d 200 t o 770 p e r c e n t on h e r b i c i d e t r e a t e d p l o t s 26 m o n th s a f t e r a p p l i c a t i o n (T a b le 1 7 ) . C o m b i n a t i o n s o f 2 , 4 —D am in e a n d 0 .07 k g / h a o f p i c l o r a m i n c r e a s e d p e r e n n i a l g r a s s p r o d u c t i o n 37 p e r c e n t when c om p a re d t o 0 .07 k g / h a o f p i c l o r a m a l o n e a t Ovando . A p p l i c a t i o n o f 2 ,4 -D a l o n e i n c r e a s e d p e r e n n i a l g r a s s p r o d u c t i o n 200 p e r c e n t a t H a r low t o n b u t c a u s e d no s i g n i f i c a n t i n c r e a s e i n g r a s s p r o d u c t i o n a t Ovando . The r e l e a s e o f p e r e n n i a l g r a s s g r o w t h i s p r o b a b l y d u e t o e l i m i n a t i o n o f t h e a l l e l o p a t h i c i n f l u e n c e o f s p o t t e d knapweed ( F l e t c h e r and Penney, 1963). Tab le 17. P e r e n n i a l G ra s s P ro d u c t io n on J u l y 20, 1984, 26 Months A f t e r th e A p p l i c a t i o n o f P ic lo r am to C on t ro l S p o t t e d Knapweed a t H a r low ton and Ovando.'' P e r e n n i a l G ra s s P ro d u c t io n (k g /h a ) H a r low ton P ic lo r am Rate 2 ,4-D Amine k g /h a k g /h a 0.00 2.24 Ovando 2 ,4-D Amine k g /h a 0 .00 2 .24 0 .2 8 807 .2 627 .2 2612 .8 2877 .6 0 .2 5 7 9 5 .2 70 5 .2 2686 .4 2928 .8 0 .2 2 841 .6 702 .8 2739 .2 3086 .4 0 .21 7 4 7 .2 656 .0 3235 .6 2658 .8 0 .1 4 702 .0 665 .6 2896 .8 2427 .6 0 .11 640 .4 75 4 .0 2517 .6 2726 .8 0 .0 7 659 .6 568 .0 1636 .4 2594 .4 0 .0 0 2 5 6 .7 54 2 .0 4 1 8 .4 48 2 .8 LSD .05 222 371 C.V. % 17 8 ^ P ic lo r am r a t e s were a p p l i e d a lo n e and in c om b in a t io n w i th 2,4-D am ine on June 16 and 17, 1982. P e r e n n i a l g r a s s p r o d u c t i o n was n e g a t i v e l y c o r r e l a t e d ( r= - .955 ) to s p o t t e d k n apw eed d e n s i t y a t Ovando ( F i g u r e 7 ) . G r a s s p r o d u c t i o n 59 d e c r e a s e d from 35 to 65 p e r c e n t a s s p o t t e d knapweed d e n s i t y i n c r e a s e d f r om 5 to 18 p l a n t s p e r q u a r t e r m e t e r s q u a r e r e s p e c t i v e l y . The c o r r e l a t i o n b e tw e e n f o r a g e y i e l d a n d s p o t t e d k n apw eed d e n s i t y was - 0 .7 9 8 a t t h e H a r l o w to n s i t e ( F i g u r e 8 ) . U t i l i z a t i o n o f g r a s s by c a t t l e i s r e s p o n s i b l e f o r t h e d e c r e a s e i n c o r r e l a t i o n a t t h i s s i t e . These o b s e r v a t i o n s a r e c o n s i s t e n t w i t h r e s u l t s r e p o r t e d by Watson and Renney (1974) f o r d i f f u s e knapweed. T h e r e w as no s i g n i f i c a n t d i f f e r e n c e i n t h e n um be r o r b i o m a s s o f o t h e r f o r b s p r e s e n t on p i c l o r a m o r p i c l o r a m / 2 , 4 - D t r e a t e d p l o t s compared to th e c o n t r o l (T ab le s 18 and 19). P ic lo r am a p p l i c a t i o n s d id n o t c a u se a s h i f t i n f o r b s p e c i e s (Appendix D1 T ab le s 40 and 4 1 ) . The T a b l e 18 . The Number o f F o r b s O th e r Than S p o t t e d Knapweed P e r 0 .09 m^ i n J u n e 1984» 24 M on th s A f t e r H e r b i c i d e A p p l i c a t i o n a t H a r low ton and OvandoJ Number o f O the r F o rb s p e r 0.09 m2 H ar low ton Ovando P ic lo r am 2,4-D Amine 2,4-D Amine Rate Rate (k g /h a ) R a te (kg /h a ) ( k g / h a ) 0.00 2.24 0.00 2.24 0 .2 8 0 .53 0 .8 8 0.11 0 .00 0 .2 5 0 .2 2 0.11 0.11 0 .00 0 .2 2 0 .44 0 .3 3 0 .2 2 0 .44 0 .21 0 .3 3 0 .3 3 0 .0 0 0 .22 0 .1 4 0.66 0 .4 4 0 .5 5 0 .88 0.11 0 .9 9 0 .9 9 0 .4 4 0 .33 0 .0 7 1 .33 1.11 0 .3 3 0 .22 0 .0 0 1 .2 2 0 .4 4 0 .0 0 0.11 LSD .05 0.64 0.44 cv% 77 93 ^ P i c l o r a m was a p p l i e d a l o n e and i n c o m b i n a t i o n w i t h 2 ,4 -D am in e on June 16 and 17» 1982 r e s p e c t i v e l y . 4 0 35 - - 0 . 9 5 5 OT x zo- Number Of Mature Spo t ted Knapweed Plants Per 0 .25 at Ovando F ig u re 7. The C o r r e l a t i o n Between P e r e n n i a l G rass P ro d u c t io n and Mature S p o t te d Knapweed D en s i ty a t Ovando. 60 - r = - 0 .7 8 8 O I Number Of mature spo t t ed Knapweed Plants Per 0.25 M2 at Harlowton F ig u re 8. The C o r r e l a t i o n Between P e r e n n i a l G ra s s P ro d u c t io n and Mature S p o t te d Knapweed D en s i ty a t H a r lo wton. 62 low number o f f o r b s p r e s e n t i n u n t r e a t e d c o n t r o l p l o t s i n d i c a t e s t h a t s p o t t e d knapweed may s u p r e s s g row th and e s t a b l i s h m e n t o f f o r b s p e c i e s . T h e s e r e s u l t s s u g g e s t t h a t low r a t e s o f p i c l o r a m do n o t i m p a i r f o r b d i v e r s i t y on k n a p w e e d - in f e s t e d r a n g e la n d . T ab le 19. The B iomass o f Forb S p e c ie s O the r Than S p o t te d Knapweed 26 Months A f t e r H e rb ic id e A p p l i c a t i o n a t H a r low ton and Ovando.'* Forb B iomass (k g /h a ) H a r low ton Ovando P ic lo r am Rate 2 ,4-D Amine k g /h a 2,4-D Amine k g /h a k g /h a 0.00 2.24 0 .00 2 .24 0 .2 8 19 .2 5 0 .8 6 .8 0 .0 0 .2 5 26 .4 4 3 .6 5 .2 8 .9 0 .2 2 63 .6 17 .3 12 .8 0 .0 0 .21 2 2 .0 7 6 .0 0 .0 14 .4 0 .1 4 104 .0 83 .2 16 .4 9 .4 0 .11 53 -2 7 8 .4 0 .0 0 .0 0 .0 7 96 .0 106 .8 6 .8 0 .0 0 .0 0 9 2 .8 104 .0 0 .0 1 5 .3 LSD .05 102 21 CV% 82 183 P ic lo r am R es idue S tudy S i g n i f i c a n t a m o u n t s o f p i c l o r a m r e m a i n e d i n t h e s o i l 26 m o n th s a f t e r a p p l i c a t i o n . Data from b o th s i t e s w i l l be d i s c u s s e d c o n c u r r e n t l y s i n c e t h e am o u n t o f p i c l o r a m i n t h e s o i l was t h e sam e a t b o t h s i t e s . A p p r o x im a t e l y 12 ppbw o f p i c l o r a m was d e t e c t e d i n s o i l a f t e r 26 m o n th s on p l o t s w h ic h w e re o r i g i n a l l y t r e a t e d w i t h 0 .28 k g / h a o f p i c l o r a m ( F i g u r e 9 ) . T h i s i s e q u i v a l e n t t o a b o u t f i v e p e r c e n t o f t h e o r i g i n a l c o n c e n t r a t i o n o f p i c l o r a m a p p l i e d . T h e r e was a l i n e a r d e c r e a s e i n t h e amoun t o f p ic lo r am r em a in in g i n th e s o i l from 12 ppbw 1 2 - 'IO- CD CL Q- < C O _ l g CL B- B- 4- 2- O- Q HARLOWTON □ OVANDO :W : f i S ■ S p o t t e d K n a p w e e d S e e d l i n g S e n s i t i v i t y L e v e l Iil . ■ fclO C O " I I L™ I I I I 0 .2 B 0 .2 5 0 .2 2 0.2n 0 .14 0/11 ORIGINAL PICLORAM RATES, KG/HA 0 .0 7 0.00 F ig u re 9. The Amount o f P ic lo r am D e te c ted i n S o i l a t H ar low ton and Ovando 26 Months A f t e r P ic lo r am A p p l i c a t io n . 64 f o r t h e h i g h e s t r a t e a p p l i e d (0 .2 8 k g / h a ) t o l e s s t h a n I ppbw f o r t h e l o w e s t r a t e a p p l i e d (0 .07 k g /h a ) . The am o u n t o f p i c l o r a m r e m a i n i n g i n t h e s e s o i l s i s g r e a t e r t h a n t h a t wh ich would be p r e d i c t e d from p u b l i s h e d l i t e r a t u r e . Hamaker e t a l . (196?) u sed th e f o l l o w in g e q u a t i o n o f h a l f - o r d e r k i n e t i c s to c a l c u l a t e th e p e r s i s t e n c e o f p i c lo r am i n s o i l : Months o f A c t i v i t y = 2(fCQ - iTC" )/K where: C0 = t r e a tm e n t r a t e oz a i /A C = amount o f p i c lo r am r em a in in g a f t e r a s p e c i f i c t im e K = h a l f o r d e r c o n s t a n t T h i s e q u a t i o n was u s e d t o c om p a re t h e e s t i m a t e d p e r s i s t e n c e o f p i c lo r am f o r Montana s o i l s to th e r e c o v e r e d p i c lo r am i n t h i s r e s i d u e s tu d y (T ab le 20). R e s u l t s showed t h a t p ic lo r am r em a in ed i n r a n g e la n d s o i l s i n Montana 40 to 50 p e r c e n t l o n g e r th an i s p r e d i c t e d by Hamaker e t a l . ( 1 9 6 7 ) . T ab le 20. The P e r s i s t e n c e o f P ic lo r am i n Montana S o i l s a s E s t im a te d by Hamaker e t a l . (1967) and t h i s Res idue S tudy . Months to r e a c h 0.6 ppbw in s o i l P i c l o r a m P r e d i c t i o n by H am aker P r e s e n t F i e l d S tu d y Rate K v a l u e s ' K v a lu e k g /h a K =0.19 K=0.25 K = 0 .11 0 .2 8 20 .0 15 .2 34-5 0 .2 5 18 .8 14 .3 32 .5 0 .2 2 17 .6 13 .3 30 .4 0.21 17 .2 1 3 .0 2 9 .6 0 .1 4 13 .8 10 .5 23 .9 0 .11 12.1 9 .2 2 0 .9 0 .0 7 9 .5 7 .2 16 .3 0 .0 0 0 .0 0 .0 0 .0 •i K v a l u e s i n d i c a t e h a l f - o r d e r c o n s t a n t s t h a t w e re c a l c u l a t e d t o p r e d i c t th e p e r s i s t e n c e o f p i c lo r am i n s o i l . 65 The e x te n d ed p e r s i s t e n c e o f p i c lo r am i n r a n g e l a n d s o i l s i n Montana may be t h e r e s u l t o f s e v e r a l f a c t o r s . F i r s t , c o o l summer a n d c o l d w i n t e r t em p e r a t u r e s , which c h a r a c t e r i z e b o th s i t e s (Appendix D, T ab le 37 ) , would s low th e r a t e o f m ic r o b i a l d e g r a d a t i o n o f p ic lo r am (G rover , 1 967 ; G o r in g e t a l . , 1 965 ; Keys a n d F r i s e n , 1 9 6 8 ) . S e c o n d , t h e r e was l i t t l e o r no l o s s o f p i c l o r a m by l e a c h i n g b e c a u s e o f t h e low r a i n f a l l r e g im e s a t th e two s tu d y s i t e s . The r e s u l t s o f t h e g r e e n h o u s e b i o a s s a y i n d i c a t e d t h a t s p o t t e d k n apw eed s e e d l i n g s a r e i n j u r e d by 8 ppbw o f p i c l o r a m i n t h e s o i l ( F ig u r e 9). T h is i n d i c a t e s t h a t p i c lo r am r a t e s o f 0.28 and 0.07 k g /h a would c o n t r o l s p o t t e d knapweed s e e d l i n g g row th f o r 29.7 and 11.5 months r e s p e c t i v e l y (T a b le 2 1 ) . R e s u l t s a l s o i n d i c a t e t h a t a l l r a t e s o f p i c l o r a m a p p l i e d i n t h e f i e l d s t u d y w i l l p r o b a b l y d r o p b e low t h e s e n s i t i v i t y l e v e l o f s p o t t e d k n a pw e ed s e e d l i n g s t h r e e y e a r s a f t e r a p p l i c a t i o n . S i n c e m o s t s e e d l i n g e s t a b l i s h m e n t u s u a l l y o c c u rs d u r in g th e s p r i n g o f th e y e a r , 0.21 k g /h a o f p i c lo r am w i l l p ro b ab ly p ro v id e t h e same l e n g t h o f c o n t r o l a s 0.28 k g /h a . T ab le 21. Leng th o f Time N ece ssa ry f o r P ic lo r am R e s id u e s to D ec rea se B e low t h e S e n s i t i v i t y L e v e l (8 ppbw) o f S p o t t e d Knapweed S e e d l i n g s . P i c l o r a m Rate o f a p p l i c a t i o n ( k g /h a ) (ppbw) E s t im a t e d M on th s R e q u i r e d f o r P ic lo r am R es idues to Reach 8 ppbw 0 .2 8 256 2 9 .7 0 .2 5 228 2 7 .7 0 .2 2 201 2 5 .6 0 .21 192 2 4 .8 0 .1 4 128 19.1 0 .11 100 16 .1 0 .0 7 78 11 .5 0 .0 0 0 0 .0 6 6 T h e se r e s u l t s h av e i m p o r t a n t i m p l i c a t i o n s f o r m an a g em en t o f s p o t t e d k n a pw e ed . The u s e o f 0.21 k g / h a o f p i c l o r a m r a t h e r t h a n t h e c u r r e n t r e com m enda tion o f 0.28 k g /h a would r e d u c e th e c o s t o f a c o n t r o l p r o g r am i n M on tan a by $2 .80 p e r a c r e ( b a s e d on t h e p r e s e n t p r i c e o f T o rd on 22K a t $ 90 .0 0 g a l l o n ) . T h e s e r e s u l t s a l s o i n d i c a t e t h a t t h e r e s i d u a l a c t i v i t y o f a l l r a t e s o f p i c lo r am a p p l i e d i n t h i s s tu d y w i l l n o t p e r s i s t beyond t h e l o n g e v i t y o f v i a b i l i t y o f s p o t t e d knapweed s e e d s i n s o i l . T h e r e f o r e , a t l e a s t one r e a p p l i c a t i o n o f p i c l o r a m w i l l be n e c e s s a r y to p r e v e n t r e i n v a s i o n o f t h i s weed from ah in d ig e n o u s s o i l - b o rn e s e ed p o p u l a t i o n . T h is s tu dy sh o u ld be c o n t in u e d to d e te rm in e th e o p t im um p i c l o r a m r a t e n e e d e d a s a r e t r e a t m e n t i n a n a t t e m p t t o e r a d i c a t e s p o t t e d knapweed. Summary | j ; I ; S p o t t e d k n apw eed i s t h e m o s t t r o u b l e s o m e weed o f r a n g e l a n d i n w e s t e r n M on ta n a . P i c l o r a m a t r a t e s o f 0 .14 t o 0 .28 k g / h a p r o v i d e d c o m p l e t e c o n t r o l o f m a tu r e s p o t t e d k n apw eed p l a n t s f o r a t l e a s t tw o r! y e a r s . P ic lo r am r a t e s be low 0.14 k g /h a shou ld n o t be recommended a s a c o n t r o l a l t e r n a t i v e s i n c e s p o t t e d k n apw eed s e e d p r o d u c t i o n was n o t c o m p le t e l y s to p p ed . L ik ew is e , th e a d d i t i o n o f 2 ,4 -D am ine to p i c lo r am ! s h o u l d n o t be r e c om m end ed s i n c e i t w i l l n o t s i g n i f i c a n t l y im p r o v e ^ c o n t r o l o v e r an a p p l i c a t i o n o f p i c l o r am a lone .. R e in v a s io n by s p o t t e d k n apw eed s e e d l i n g s o c c u r r e d 26 m o n th s f o l l o w i n g a p p l i c a t i o n o f p i c l o r am a t r a t e s be low 0.21 k g /h a . R em ova l o f s p o t t e d k n apw eed f r o m t h e p l a n t c om m un i ty w i t h h e r b i c i d e s r e s u l t e d i n g r a s s p r o d u c t i o n i n c r e a s e s o f 200 t o 770 67 p e r c e n t . The i n c r e a s e i n g r a s s p r o d u c t i o n was s t r o n g l y c o r r e l a t e d to s p o t t e d k n apw eed d e n s i t y ; a s s p o t t e d k n apw eed d e n s i t y i n c r e a s e d , p e r e n n i a l g r a s s p r o d u c t i o n d e c r e a s e d . There were no a d v e r s e changes i n p l a n t d i v e r s i t y , p l a n t n um b e r , o r b i o m a s s p r o d u c t i o n o f o t h e r f o r b s p e c i e s on t h e two s i t e s a s a r e s u l t o f p i c lo r am a p p l i c a t i o n s . P ic lo r am r e s i d u e s a r e th e m o s t im p o r t a n t f a c t o r i n d e te rm in in g th e l o n g e v i t y o f c o n t r o l o f s p o t t e d knapweed;- R e s u l t s o f th e r e s i d u e s tu d y i n d i c a t e t h a t none o f t h e p i c lo r am r a t e s t e s t e d w i l l r em a in i n th e s o i l l o n g e n o u g h t o e x h a u s t t h e s e e d r e s e r v e o f s p o t t e d k n a p w e e d . T h e r e f o r e , a t l e a s t one r e a p p l i c a t i o n o f p i c lo r am w i l l be n e c e s s a r y i n o r d e r t o e r a d i c a t e s p o t t e d knapweed from an i n f e s t e d s i t e . 68 CHAPTER 6 THE EFFECT OF 2 ,4 -D ON TWO STRAINS OF SPOTTED KNAPWEED A b s t r a c t D i f f e r e n t i a l t o l e r a n c e to 2 ,4 -D ( 2 , 4 - d ic h lo ro p h e n o x y ) a c e t i c a c i d ) was o b s e rv ed i n s p o t t e d knapweed ( C en tau re a m acu lo sa Lam.) i n f i e l d e x p e r im e n t s condu c ted a t H arlow ton and Ovando, Montana . P l a n t s were c o l l e c t e d from b o th l o c a t i o n s and grown u nd e r i d e n t i c a l c o n d i t i o n s f o r f i e l d and l a b o r a t o r y e v a l u a t i o n . E x p e r im en ta l r e s u l t s i n d i c a t e d t h a t t h e r e were no d i f f e r e n c e i n r e s p o n s e to 2 ,4 -D a p p l i c a t i o n s be tw een ; p l a n t s from th e two l o c a t i o n s when grown t o g e a t h e r . A p p l i c a t i o n o f 2 . 4 - D a t 2 .2 4 k g /h a c au sed s l i g h t i n j u r y symptoms to b o th s t r a i n s o f s p o t t e d knapweed. L a b o r a to ry s t u d i e s showed t h a t t h e r e was no d i f f e r e n c e i n u p ta k e o f ^ C 2 ,4 -D be tw een th e two s t r a i n s when l e a f s u r f a c e p ubescence was i n t a c t . Twenty f o u r p e r c e n t o f t h e a p p l i e d 14A 2 . 4 - D was t a k e n up by e x c i s e d l e a v e s i n 48 h o u r s . Uptake doub led when l e a f s u r f a c e pub e scen ce was removed. R a d io la b e le d 2 ,4 -D t r a n s l o c a t e d t h ro u g h o u t p l a n t s w i t h in one day f o l l o w in g t r e a tm e n t . There was no d i f f e r e n c e be tw een ■ th e two s t r a i n s i n th e amount o f 2 ,4 -D t h a t was t r a n s l o c a t e d to d i f f e r e n t p l a n t p a r t s , I , 4 , and 8 day s f o l l ow in g a p p l i c a t i o n . However, ■th e c o n c e n t r a t i o n o f 2 ,4 -D was 3 .3 t im e s g r e a t e r i n th e crown o f p l a n t s from Harlow ton compared to Ovando p l a n t s 12 days f o l l o w in g a p p l i c a t i o n . The o b s e rv ed t o l e r a n c e t o 2 ,4 -D i n t h e 69 i n i t i a l f i e l d s t u d i e s a p p e a r s to be t h e r e s u l t o f d i f f e r e n c e s i n p l a n t v i g o r r a t h e r th an d i f f e r e n c e s i n u p tak e o r t r a n s l o c a t i o n o f th e h e r b i c i d e . I I n t r o d u c t i o n V a r i a t i o n s i n i n t e r s p e c i f i c t o l e r a n c e to 2 ,4 -D have been r e p o r t e d . Hodgson (1970) r e p o r t e d t h a t t e n e c o ty p e s o f Canada t h i s t l e ( C irs ium a r v e n s e ) r e sp ond ed d i f f e r e n t l y to 2 ,4 -D . D i f f e r e n c e s in r e sp o n se to 2 ,4 -D have a l s o been r e p o r t e d be tw een s t r a i n s o f f i e l d b indweed (C onvo lvu lu s a r v e n s e s ) (W h itw o r th , 1 964 ) , h o a ry c r e s s (C a rd a r i a c h a l a p e n s i s ) ( Sexsm it h , 1 964 ) , w i ld c a r r o t (Daucus c a r o t a ) (Whitehead and S w i t z e r , 1 963 ) , and k o ch ia (Kochia s c o p a r i a ) ( B e l l e t a l . , 1972 ) . F i e l d s t u d i e s i n d i c a t e t h a t some s t r a i n s o f s p o t t e d knapweed may be t o l e r a n t to 2 ,4 -D . S p o t t e d knapweed c o n t r o l one y e a r f o l l o w in g a p p l i c a t i o n o f 2 .2 4 k g /h a o f 2 ,4 -D r a n g ed from 21 to 100 p e r c e n t a t Ovando and Harlo 'w ton , Montana, r e s p e c t i v e l y ( C h ic o in e , 1984) • V a r i a t i o n i n t h e r e s p o n s e o f s p o t t e d knapweed to 2 ,4 -D h a s a l s o been r e p o r t e d by W a t te n b a rg e r e t a l . , ( 1 9 80 ) . • A d d i t i o n a l i n f o rm a t io n c o n c e rn in g th e v a r i a t i o n i n s u s c e p t i b i l i t y o f s p o t t e d knapweed to 2 ,4 -D i s n e e d e d " to u n d e r s t a n d th e p o t e n t i a l o f t h e weed to d e v e lo p t o l e r a n c e to t h e h e r b i c i d e , and e x p l a i n . i n c i d e n t s o f in c om p le te weed c o n t r o l . S p e c i f i c o b j e c t i v e s o f t h i s s tu d y were t o : (1 ) e v a l u a t e ' t h e e f f e c t o f 2 ,4-D on two s t r a i n s o f s p o t t e d knapweed when grown a t one f i e l d l o c a t i o n , and (2 ) measure 2 ,4 -D up tak e and movement be tw een two s t r a i n s o f s p o t t e d knapweed. ' 70 M a te r i a l s and Methods M atu re s p o t t e d knapweed p l a n t s w h ich were n o t c o n t r o l l e d by 2 ,4-D w e re c o l l e c t e d on N ovem be r 13 , 1983 a t O vando , M on tan a f rom p l o t s t r e a t e d f o r t w o ■s u c c e s s i v e y e a r s w i t h 2 .2 4 k g / h a o f 2 ,4 -D . M a tu r e p l a n t s were a l s o c o l l e c t e d from a p o p u l a t i o n n e a r H a r lo wton, Montana, on November 14, 1983. A lthough t h e s e p l a n t s had n o t been t r e a t e d w i th 2 ,4 -D , o t h e r p l a n t s g r o w in g a t t h e s i t e w e re f o u n d t o be e x t r e m e l y s e n s i t i v e to t h e h e r b i c i d e . P l a n t s f rom b o th s i t e s were t r a n s p o r t e d to Bozeman, M ontana , f o r c o n t r o l l e d f i e l d and l a b o r a t o r y s t u d i e s . F i e l d S tudy F i f t y s p o t t e d knapweed p l a n t s from e a ch l o c a t i o n were p l a n t e d a t t h e P o s t Agronomy Farm, Bozeman, d u r in g November, 1983. P l a n t s were sp a ced 0 .9 m e te r s a p a r t w i t h a t h r e e m e te r b u f f e r s t r i p s e p a r a t i n g th e two s t r a i n s . The s o i l a t t h e s tu d y s i t e was c l a s s i f i e d a s Bozeman s i l t loam (A rg ic P a ch ic C ry o b o ro l l ) w i t h t h r e e p e r c e n t o r g a n ic m a t t e r i n t h e 0 to 20 cm d e p th . Average mon th ly t em p e r a tu r e and p r e c i p i t a t i o n d a ta f o r t h e s tu d y a r e a i s shown i n th e Appendix D, (T ab le s 42 and 43 ) . The s o i l had been f a l l o w e d f o r one y e a r p r i o r to p l a n t i n g . P l a n t s were e v a l u a t e d on A p r i l 13, 1984 f o r w i n t e r i n j u r y . P l a n t s t h a t were w i n t e r k i l l e d were r e p l a c e d w i t h g reenhou se -g row n p l a n t s from th e r e s p e c t i v e l o c a t i o n s . P l a n t h e i g h t , number o f s tem s , and d a t e o f f l o w e r i n g was r e c o rd e d f o r e a c h p l a n t d u r in g t h e summer. B o l t h e i g h t was m easu red on June 17 and 29, and J u l y 11 and 26. The number o f s tem s p e r p l a n t was r e c o rd e d 71 on J u l y , 26 . Date o f f l o w e r in g was r e c o rd e d on J u l y 11, 15, 26 , and 30 , and on August 2 and 9 , 1984. H e rb ic id e t r e a tm e n t s o f 0 .0 , 1 .1 2 , and 2 .2 4 kg a . i . / h a o f th e d ie th a n o lam in e s a l t o f 2 ,4 -D were a p p l i e d on June 29 , 1984. P l o t s were a r r a n g e d i n a random ized com p le te b lo c k d e s ig n w i th t h r e e r e p l i c a t i o n s p e r t r e a tm e n t . There were f i v e p l a n t s p e r p l o t . P l a n t h e ig h t a t th e t im e o f h e r b i c i d e a p p l i c a t i o n a v e ra g e d 50 cm f o r p l a n t s from Ovando, and 24 cm f o r p l a n t s from H a r low to n . The 2 ,4 -D was a p p l i e d w i th a CO2 p r e s s u r i z e d b ackpack s p r a y e r i n 167 I / ha o f w a t e r . P l a n t i n j u r y was e v a lu a t e d v i s u a l l y , u s in g a 0 to 10 s c a l e , where 0 and 10 i n d i c a t e d no i n j u r y , and d e a th o f a p l a n t r e s p e c t i v e l y . I n j u r y r a t i n g s were t a k e n on J u ly 7 and August 2 , 1984. Above g round b iom ass was h a rv e s t e d on August 9$ oven d r i e d a t 50 C f o r 48 h o u r s , and w e ighed . P l a n t s were a l low ed to r e g r o w . a f t e r h a r v e s t and 2 ,4 -D was a p p l i e d i n t h e f a l l to p l a n t s i n th e r o s e t t e g row th s t a g e . The d ie th a n o lam in e s a l t o f 2 ,4 -D was a p p l i e d a t r a t e s o f 0 .0 and 2 .2 4 kg a . i . / h a to e a ch s t r a i n on Sep tember 3 , 1984 a s d e s c r i b e d a b o v e . P l a n t i n j u r y was e v a l u a t e d on Sep tember 5 , and 15, and on O c tober 12 , 1984 u s in g th e method d e s c r i b e d above f o r t h e June h e r b i c i d e a p p l i c a t i o n . Uptake S t u d i e s S p o t t e d knapweed p l a n t s u sed f o r th e l a b o r a t o r y s t u d i e s were p o t t e d i n 1 .8 l i t e r c o n t a i n e r s i n November, 1983. They were grown i n th e g re en hou se f o r s i x months w i th 16C day t em p e ra tu r e and 21C n i g h t t e m p e r a t u r e . F l u o r e s c e n t l i g h t s were u sed to e x te n d th e p h o to p e r io d to 16 h o u rs p e r d ay . 72 S ix s p o t t e d k n apw eed p l a n t s f r om H a r l o w ton a n d s i x p l a n t s f r om Ovando w e re s e l e c t e d f o r t h e s t u d y . F o u r l e a v e s w e re t a k e n f rom t h e b a s a l r o s e t t e o f e a c h p l a n t . T h i s s a m p l i n g sch em e a l l o w e d one l e a f f rom e a ch p l a n t - to be r e p r e s e n t e d i n e a ch t r e a tm e n t . The l e a v e s were e x c i s e d w h i le t h e whole p l a n t was subm ersed i n w a te r t o m in im ize xylem p l u g g i n g ( R i c h a r d a n d S l i f e , 1 9 7 9 ) . E a ch l e a f w as p l a c e d i n a 2 cm d i a m e t e r by 15 cm lo n g t e s t tu b e c o n t a i n i n g 35 m is o f g l a s s - d i s t i l l e d , d e - g a s s e d w a te r . While subm ersed , 0.5 cm o f l e a f t i s s u e was removed f r om t h e c u t end o f t h e l e a f . The l e a v e s , w e re p l a c e d i n t h e d a r k a t 21 C. A f t e r 45 m i n u t e s , t h e l e a v e s w e re r em ov ed f r o m t h e d a r k a n d p l a c e d u n d e r 234 u E /m 2 / s e c o f l i g h t i n t e n s i t y a t 21 C f o r a o n e - h o u r e q u i l i b r a t i o n p e r i o d . R e l a t i v e h u m i d i t y o f t h e l e a f s u r f a c e was m e a s u r e d w i t h a L i c o r a u t o p o r o m e t e r t o d e t e r m i n e i f t h e l e a f w as a c t i v e l y t r a n s p i r i n g . Only l e a v e s t h a t were a c t i v e l y t r a n s p i r i n g were u sed i n t h e s tu d y . The s u r f a c e p u b e s c e n c e on t h e a d a x i a l s u r f a c e o f 12 l e a v e s f r om e a ch s p o t t e d knapweed s t r a i n was removed by r u b b in g th e l e a f t e n t im e s b e tw een th e f o r e f i n g e r and thumb. Twelve l e a v e s f rom e a ch s t r a i n were n o t r u b b e d a n d s e r v e d a s c o n t r o l s . U n i f o rm ly r i n g l a b e l e d 2 ,4 -D (0 .0 8 uCi) was a p p l i e d i n f o u r , 0.5 u l d r o p s t o th e a d a x i a l s u r f a c e o f e a ch l e a f . R a d i o l a b e l e d 2 ,4 -D was r e c e i v e d a s ( 2 , 4 - d i c h l o r o p h e n o x y ) a c e t i c a c i d r i n g U L - ^ C l a b e l e d (100 uC i ) w i t h s p e c i f i c a c t i v i t y o f 9 .0 u C i / m mole . The 2 ,4 -D was d i s s o l v e d i n 500 u l o f 50 p e r c e n t e t h a n o l . A 150 u l a l i q u o t was removed from t h i s s o l u t i o n and combined w i t h d i e t h a n o l a m i n e i n a 1:1 m o l a r c o n c e n t r a t i o n . The d i e th a n o lam in e 73 s a l t o f 14c 2 ,4 -D was d i l u t e d w i t h 50 p e r c e n t e th a n o l and 90 u l o f a s o l u t i o n c o n t a i n i n g c om m erc ia l ly f o rm u la t e d d ie th a n o lam in e s a l t o f 2 . 4 - D ( 0 .2 8 kg a . i . / h a ) to p r o v id e a t o t a l volume o f 600 u l w i th 2 8 .8 uCi o f a c t i v i t y . Uptake was m easu red a t 24 and 48 hou rs a f t e r a p p l i c a t i o n o f 14c 2 . 4 - D. A t th e end o f e a c h u p tak e p e r i o d , s i x rubbed and s i x un rubbed l e a v e s from e a ch s t r a i n were removed from th e d e -g a s s e d w a te r . Each l e a f was p l a c e d i n a 35 ml t e s t tu b e and r i n s e d t h r e e t im es f o r 30 s e cond s w i th 10 ml o f 50 p e r c e n t e t h a n o l by a g i t a t i n g on a v o r t e x m ix e r . T h is t e c h n iq u e e n su re d rem ova l o f u n ab so rb ed 140 2 ,4 -D from th e l e a f s u r f a c e . The wash s o l u t i o n s , were combined and b ro u g h t to a t o t a l volume o f 3 0 .0 ml w i th 50 p e r c e n t e t h a n o l . A 1 .0 ml a l i q u o t was removed and p l a c e d i n a s c i n t i l l a t i o n v i a l w i th 15 ml o f Hydrocoun t S c i n t i l l a t i o n F l u id 1 . T o ta l volume o f t h e d e -g a s s e d w a te r s o l u t i o n was r e c o r d e d and a 1 ml a l i q u o t was p l a c e d i n a s c i n t i l l a t i o n v i a l w i th 15 ml o f H ydrocoun t S c i n t i l l a t i o n F l u id . The r a d i o a c t i v i t y i n th e v i a l s was m easu red f o r 10 m in u te s by l i q u i d s c i n t i l l a t i o n s p e c t r o m e te r y A l l t r e a tm e n t s were r e p l i c a t e d s i x t im es i n a c o m p le te ly random ized d e s i g n . The e x p e r im en t was condu c ted tw i c e , and th e d a ta shown i n f o r b o th e x p e r im e n t s combined u n l e s s o th e rw is e s t a t e d . 1 H yd rocoun t i s m anu fa c tu red by J . T . Baker Chem ica ls B .V . , D e v e n t e r , H o l lan d . ^ T r i -C a rb model 2002, P ack a rd I n s t r u m e n t Co ., Downers Grove, IL 74 T r a n s l o c a t i o n S t u d i e s M ature s p o t t e d knapweed p l a n t s were grown i n th e g reenhou se a s d e s c r i b e d above f o r u p ta k e s t u d i e s . P l a n t s o f u n i fo rm s i z e and g row th s t a g e were s e l e c t e d f o r th e s tu d y . A b r o a d c a s t a p p l i c a t i o n o f c om m e rc ia l ly f o rm u la t e d d i e th a n o lam in e s a l t o f 2 ,4^D was a p p l i e d to e a ch p l a n t a t 0 .2 8 kg a . i . / h a i n 196 l / h a o f w a te r u s in g a g reenhou se b e l t s p r a y e r . Im m ed ia te ly a f t e r a p p l i c a t i o n , ^ 2 , 4-D a c id (0 .4 8 5 uCi) was a p p l i e d i n 10, 1 u l d ro p s t o t h e a d a x i a l s u r f a c e o f one l e a f . The t r e a t e d l e a f was l o c a t e d on th e low e r p o r t i o n o f th e r o s e t t e and marked w i th a p a p e r t a g . The p l a n t s were p l a c e d i n a g row th chamber w i t h a 16 hou r p h o to p e r io d w i th a d a y / n i g h t t em p e ra tu r e o f 22 /20 C, r e s p e c t i v e l y . L i g h t was p r o v id e d by f l u o r e s c e n t and i n c a n d e s c e n t t u b e s and th e i n t e n s i t y a t t h e b a se o f th e p l a n t crown was 234 uE /m 2 /sec . P l a n t s were h a r v e s t e d 1 , 4 , 8 , and 12 days a f t e r a p p l i c a t i o n o f 14C 2 , 4~D. The t r e a t e d l e a f was removed and washed t h r e e t im es i n 50 p e r c e n t e t h a n o l to remove th e r a d i o a c t i v e 2 , 4-D a s d e s c r i b e d unde r t h e u p ta k e s t u d i e s a bov e . The r em a in in g p l a n t was s e c t i o n e d i n t o th e f o l l o w in g p a r t s : l e a v e s w i th t h e t r e a t e d l e a f , o t h e r l e a v e s , c row n , u pp e r r o o t sy s tem , and lower r o o t sy s tem (F ig u re 1 0 ) . Each p l a n t p a r t , i n c l u d i n g th e t r e a t e d l e a f , was im m ed ia te ly f r o z e n w i th d ry i c e , l y o p h o l i z e d , and w e ighed . P l a n t p a r t s were homogenized w i th m o r ta r and p e s t l e . Samples (100 mg) were t a k e n from th e homogenized m a t e r i a l and o x id i z e d i n a b i o l o g i c a l m a t e r i a l o x i d i z e r ^ f o r t h r e e m in u te s . The 3 3 Harvey O x id i z e r , Ox 300, Harvey I n s t r u m e n t C o . , 123 P a t t e r s o n S t . , H i l l s d a l e , N .J . 75 1 T r e a t e d l e a f L e a v e s wi th th t r e a t e d l ea f F i g u r e 10. S p o t t e d Knapweed P l a n t P a r t s T h a t Were C o l l e c t e d t o D e te rm ine Reg ions o f 2 ,4-D A ccum u la tion . I76 o x i d i z e r e f f i c i e n c y d a t a i s shown i n Appendix D, ( F ig u r e s 18 and 19). The was t r a p p e d i n Carbon 14 C o c k t a i l 4a s 14A CO2. The ^4c c o n te n t w a s t h e n m e a s u r e d . f o r 10 m i n u t e s i n a l i q u i d s c i n t i l l a t i o n s p e c t r o m e t e r . A l l t r e a t m e n t s w e r e r e p l i c a t e d f o u r t im e s i n a c o m p le t e l y random ized d e s ig n . R e s u l t s F i e l d S t u d i e s T h e r e was a s i g n i f i c a n t d i f f e r e n c e i n g r o w t h r a t e a n d d a t e o f f l o w e r i n g b e tw een p l a n t s c o l l e c t e d a t H a r l o w to n ( s u s c e p t i b l e s t r a i n ) a n d Ovando ( t o l e r a n t s t r a i n ) ( F i g u r e s 11 a n d 1 2 ) . P l a n t s f r om Ovando I had a f a s t e r g row th r a t e and began f l o w e r i n g e a r l i e r th a n p l a n t s from H a r l o w to n . The n um b e r o f s t e m s p e r p l a n t was t h e sam e f o r t h e tw o s t r a i n s . T h e r e w e re s i g n i f i c a n t d i f f e r e n c e s b e tw e e n t h e tw o s t r a i n s o f s p o t t e d knapweed i n r e s p o n s e to t h e June a p p l i c a t i o n o f 2 .24 k g /h a o f 2 ,4-D (Tab le 22). P l a n t s from Ovando showed more i n j u r y symptoms th a n p l a n t from H a r low ton , however , t h e l e v e l o f i n j u r y f o r b o th s t r a i n s was v e r y l ow . None o f t h e p l a n t s g row n i n t h e s t u d y w e re k i l l e d by t h e , h e r b i c i d e a p p l i c a t i o n i n June . A m a jo r p rob lem w i t h th e June a p p l i c a t i o n was t h a t t h e two s t r a i n s o f s p o t t e d k n apw eed w e re i n d i f f e r e n t g r o w t h s t a g e s . P l a n t s f rom Ovando were g row ing more r a p i d l y and a v e ra g e d 50 cm i n h e i g h t compared to 24 cm f o r p l a n t s f rom H ar low ton . A c t iv e ly g row ing p l a n t s a r e more 4 Carbon 14 C o c k ta i l i s m anu fa c tu red by R.J. Harvey I n s t r u m e n t Corp. C 5 O i - C 4 0 4 7 / 2 67 / 1 16 / 2 96 / 1 7 Date F ig u re 11. The B o l t H e ig h t o f S p o t te d Knapweed P l a n t s C o l l e c t e d From H ar low ton and Ovando, Montana from June 17 to J u ly 26, 1984. 1 B ars w i th th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . C 9 0 Ovando Li. 7 0 Harlowton 0) 3 0 7 / 2 7 7 / 3 I7 / 1 5 7 / 2 37 / I 1 7 / I 9 Date From First F lower F igure 12. The P ercen t o f Spo tted Knapweed P lan ts C o lle c ted From Harlowton and Ovando That Were F low ering from Ju ly 11 to August 8, 1984. I P o in ts a t the same date fo llow ed by the same l e t t e r are n o t s ig n i f i c a n t ly d i f f e r e n t a t the 5 p erc en t l e v e l u s in g the LSD t e s t . 79 T a b l e 22 . I n j u r y R a t i n g s f o r S p o t t e d Knapweed P l a n t s C o l l e c t e d a t Ovando a n d H a r l o w to n 40 D ays A f t e r F o l i a r T r e a tm e n t W ith D ie th a n o lam in e S a l t o f 2,4-D.^ Date o f 2 ,4-D A p p l i c a t i o n 2,4-D kg /h a 6/29/84 Ovando H a r low ton 9/3/84 Ovando H a r lo w ton 0 .00 O.OOa^ 0.00a 0.00a 0.00a 1.12 1.00b 0.80b — — 2 .2 4 4»40d 2.10c 4.60b 6.10b 1I n j u r y R a t in g s a r e b a sed on v i s u a l o b s e r v a t i o n s where 0 = no i n j u r y a n d 10 = d e a t h o f p l a n t . ^M ean s i.n c o lu m n s f o r e a c h d a t e f o l l o w e d by t h e same; l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5% l e v e l u s in g th e LSD t e s t . s u s c e p t i b l e t o 2 ,4 -D ( B e l l e t a l . , 1 9 7 2 ) , w h ic h c o u l d e x p l a i n t h e d i f f e r e n c e s i n r e s p o n s e to th e 2 ,4-D a p p l i c a t i o n s . The a p p l i c a t i o n o f 2 .2 4 k g / h a o f 2 ,4 -D r e d u c e d a b o v e - g r o u n d b i o m a s s 50 a n d 45 p e r c e n t i n p l a n t s f rom Ovando and H a r lo wton, r e s p e c t i v e l y (Table 23). There was no s i g n i f i c a n t r e d u c t i o n i n b iom ass w i t h th e a p p l i c a t i o n o f 1.12 k g /h a o f 2 ,4 -D i n p l a n t s f r om e i t h e r l o c a t i o n . The d i f f e r e n c e i n p l a n t h e i g h t a n d r e l a t i v e v i g o r b e tw e e n t h e tw o s t r a i n s i s e v i d e n t i n t h e a b ov e -g ro und b iom ass m easu rem en ts . P l a n t s from H a r low ton weighed an a v e ra g e o f 65 p e r c e n t l e s s th an p l a n t s from Ovando i n b o th t r e a t e d and u n t r e a t e d p l o t s (T ab le 23). P l a n t s r e c e i v i n g a f a l l a p p l i c a t i o n o f 2 ,4 -D e x h i b i t e d i n j u r y symptoms two days a f t e r h e r b i c i d e a p p l i c a t i o n . I n c o n t r a s t to th e June a p p l i c a t i o n , p l a n t s f r om H a r lo w to n t r e a t e d i n t h e f a l l w e re i n j u r e d m ore t h a n p l a n t s f rom Ovando , h o w e v e r , t h e d i f f e r e n c e s w e re n o t s t a t i s t i c a l l y s i g n i f i c a n t ( T a b le 22 ) . The d i f f e r e n c e i n r e s p o n s e o f th e two s t r a i n s to s p r i n g and f a l l a p p l i c a t i o n s o f 2 ,4-D s u g g e s t s t h a t 80 Tab le 23- Above Ground Dry W eigh t B iomass o f S p o t t e d Knapweed S t r a i n s C o l l e c t e d f rom H a r l o w to n and Ovando. P l a n t s w e re T r e a t e d w i t h 2 .2 4 , 1 .1 2 , a n d 0 .00 k g / h a o f 2 ,4 -D on 6 - 2 9 - 8 4 a n d H a r v e s t e d o n A u g u s t s , 1984« . Dry W eigh t B iomass ( g / p l a n t ) 2 ,4-D (k g /h a ) Ovando Har low ton 0.00 178.7b1 61 .Oa 1 .12 178.7b 41.4a 2.24 90.4a 33 .8 a 1 Means f o l l o w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t . a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . g r o w t h r a t e i s a f a c t o r w h ic h a f f e c t s t h e s e n s i t i v i t y o f s p o t t e d knapweed to th e h e r b i c i d e . R e s u l t s o f t h e s e f i e l d s t u d i e s i n d i c a t e t h e r e i s no d i f f e r e n c e i n r e s p o n s e t o 2 ,4 -D b e tw e e n t h e tw o s t r a i n s o f s p o t t e d k n apw eed when g row n u n d e r i d e n t i c a l e n v i r o n m e n t a l c o n d i t i o n s . D i f f e r e n c e s i n t h e r a t e o f g row th and d a te o f f l o w e r i n g b e tw een th e two s t r a i n s may be due e i t h e r to g e n e t i c d i f f e r e n c e s b e tw een p l a n t s from th e two l o c a t i o n s o r d i f f e r e n c e s i n p l a n t v ig o r . Uptake S t u d i e s T h e r e w as no d i f f e r e n c e i n u p t a k e o f 2 ,4 -D b e tw e e n t h e tw o s t r a i n s o f s p o t t e d k n apw eed o v e r a 48 h o u r p e r i o d i n l e a v e s w i t h t h e p u b e s c e n c e i n t a c t . H ow ev e r , t h e u p t a k e was s i g n i f i c a n t l y g r e a t e r i n l e a v e s e x c i s e d f rom Ovando p l a n t s when t h e s u r f a c e p u b e s c e n c e w as removed (T ab le 24 ). Uptake was a l s o 50 p e r c e n t g r e a t e r i n l e a v e s w i t h t h e l e a f p u b e s c e n c e r em o v e d c om p a r e d t o l e a v e s w i t h t h e p u b e s c e n c e i n t a c t . Uptake c o n t in u e d to i n c r e a s e i n rubbed l e a v e s a f t e r 24 hou rs . 81 The p e r c e n t ^4A 2 ,4-D r e c o v e r e d i n rubbed l e a v e s i n c r e a s e d from 41 to 47 p e r c e n t r e s p e c t i v e l y 24 and 48 h o u r s f o l l o w i n g a p p l i c a t i o n ( T a b l e 2 5 ) . T a b l e 2 4 . T o t a l DPM's o f 14A 2 , 4 -D R e c o v e r e d Over a 48 Hour P e r i o d i n t h e L e a f Wash, S o l u t i o n , a nd L e a v e s E x c i s e d From S p o t t e d Knapweed P l a n t s C o l l e c t e d From Har low ton and O v a n d o .^ T o ta l DPM's Pubescence Harlow ton I n t a c t Ovando Pubescence Harlow ton Removed Ovando L ea f Wash2 136000c 135700c 108500b 97990a S o lu t i o n 116a 159a 202a 300a T re a t e d L ea f 34220a 34520a 61690b 72100c T o ta l DPM' s'* 170336 170379 170392 170390 ^170 ,400 DPM's were a p p l i e d to th e l e a f s u r f a c e . ^M ean s w i t h i n t h e same row f o l l o w e d by t h e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . T a b l e 25 . The P e r c e n t o f 14C 2 ,4 -D T h a t was A b so rb e d i n L e a v e s W ith Pubescence Removed and Pubescence I n t a c t 24 and 48 Hours F o l low in g A p p l i c a t i o n .2 Hours A f t e r 14C Absorbed T re a tm en t Pubescence I n t a c t Pubescence Removed 241 % (DPM) % (DPM) 19 .9 (33910 )c 4 0 .7 (69353)b 48 23 .4 (3 9874 )c 4 6 .8 (79747 )a 4 Means f o l l o w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5% l e v e l u s in g th e LSD t e s t . p Data shown a r e f o r one e x p e r im e n t w i t h H a r low ton and Ovando p l a n t s combined . ^ 170 ,400 DPM's were a p p l i e d to th e l e a f s u r f a c e . 82 ■ S u r fa c e pub e scen ce a p p e a r s to be im p o r t a n t i n r e g u l a t i n g u p tak e o f 2 . 4 - D i n t o s p o t t e d knapweed l e a v e s e s p e c i a l l y i n p l a n t s c o l l e c t e d from Ovando. The amoun t o f 2 ,4-D t a k e n up by p u b e s c e n t l e a v e s was o n ly 23 p e r c e n t c o m p a r e d t o 47 p e r c e n t f o r l e a v e s w i t h t h e p u b e s c e n c e removed . A l though c a r e was ta k en i n rem ov ing pubescence from th e l e a f s u r f a c e , i t i s p o s s i b l e t h a t a d d i t i o n a l damage may have o ccu red to th e l e a f c u t i c l e . T h is c o u ld have i n f l u e n c e d th e amoun t o f 2,4-D ab so rb ed . I n e f f e c t i v e u p t a k e o f 2 ,4 -D may be a m a j o r f a c t o r w h ic h e x p l a i n s t h e u n a c c e p t a b l e c o n t r o l o f t e n a c h ie v e d w i th f i e l d a p p l i c a t i o n s . T r a n s l o c a t i o n S t u d i e s R e s u l t s from th e t r a n s l o c a t i o n s t u d i e s i n d i c a t e t h a t r a d i o l a b e l e d 2 . 4 - D i s t r a n s l o c a t e d t h r o u g h o u t b o th s t r a i n s o f s p o t t e d knapweed one day f o l l o w i n g a p p l i c a t i o n ( T a b le 26 ) (A p p e n d ix , T a b l e 46,). The c o n c e n t r a t i o n o f 2 ,4 -D r e c o v e r e d i n l e a v e s w i t h t h e t r e a t e d l e a f w as s i g n i f i c a n t l y g r e a t e r i n p l a n t s f r om Ovando c om p a r e d t o p l a n t s from H a r low to n one day f o l l o w in g a p p l i c a t i o n . However, t h e r e was no d i f f e r e n c e i n t h e amoun t o f 1WA 2 ,4-D t r a n s l o c a t e d t o o t h e r p l a n t p a r t s be tween, t h e two s t r a i n s 1, 4 , and 8 day s f o l l o w in g a p p l i c a t i o n . The h i g h e s t c o n c e n t r a t i o n o f 2 ,4 -D r e m a i n e d i n t h e t r e a t e d l e a f th r o u g h o u t t h e s tu d y p e r io d . S i g n i f i c a n t d i f f e r e n c e s i n t r a n s l o c a t i o n p a t t e r n s were d e t e c t e d f o r t h e tw o s t r a i n s 12 d a y s a f t e r a p p l i c a t i o n (T a b le 2 6 ) . The am o u n t o f 2 ,4 -D r e c o v e r e d f r om t h e p l a n t c row n was g r e a t e r f o r H a r l o w to n p l a n t s . H ow ev e r , b a s e d on t h e r e s u t s o f t h e f i e l d s t u d i e s , t h i s d i f f e r e n c e i n t r a n s l o c a t i o n b e tw een th e two s t r a i n s doe s n o t a p p e a r to be g r e a t enough t o c a u se a d i f f e r e n t i a l r e sp o n se to 2 ,4-D . T ab le 2 6 . The C o n c e n tra t io n o f 2 ,4 -D ( e x p re s se d a s DPM's p e r gram o f d ry t i s s u e ) T h a t Was R ecovered in D i f f e r e n t P a r t s o f S p o tte d Knapweed P la n t s from H arlow ton (H) and Ovando (O ) , M ontana, I , 4 , 8 and 12 Days F o llow ing A p p l ic a t io n . !I1I1 Os p e r gram d ry w e igh t Days A f te r a p p l i c a t i o n P l a n t P a r t 1 4 8 12 I t r e a t e d l e a f 713600a 1685100a 498700a 477100a 438300a 580300b 406100a 473200a le a v e s w ith t r e a t e d l e a f 11440a 5841b 20020a 18200a 12890a 8962a 7555a 14800b o th e r le a v e s 1793a 757a 1452a 1507a 2131a 987a 1697a 1183a crown 6009a 5191a 9844a 11620a 9860a 9289a 20690b 6194a uppe r r o o t 2462a 971a 2996a 3828a 5134a 4855a 5657a 2914a low er r o o t 443a 295a 1757a 1836a 3011a 1949a 3568a 2059a 1 Means in rows f o r e a ch d a te fo llow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . t o t a l o f 1 ,0 6 7 ,0 0 0 DPM's were a p p l ie d to each p l a n t . 84 D is c u s s io n F i e l d o b s e r v a t i o n s o f h e r b i c i d e t r i a l s a t Ovando a n d H a r lo w to n , M o n ta n a , i n d i c a t e d t h a t c o n t r o l o f s p o t t e d k n apw eed w i t h 2 ,4 -D w as e r r a t i c . C o n tro l le d f i e l d and l a b o r a to r y s tu d i e s showed no d i f f e r e n c e i n r e s p o n s e to 2 ,4 -D b e tw e e n s t r a i n s f rom e a c h l o c a t i o n when g row n t o g e t h e r . B o th s t r a i n s e x h i b i t e d t o l e r a n c e to 2 ,4 -D u n d e r o p tim um g row in g c o n d i t io n s . The d i f f e r e n t i a l re sp o n se to 2 ,4-D i n O r ig in a l f i e l d s tu d i e s may be due t o d i f f e r e n c e s i n th e r e l a t i v e v i g o r o f t h e p l a n t s g r o w in g a t t h e tw o l o c a t i o n s . D a ta f rom th e f i e l d l o c a t i o n s sh ow s t h a t a b o v e g round b iom ass o f s p o t t e d knapweed was 37 p e r c e n t g r e a t e r a t Ovando t h a n H a r lo w to n ( C h i c o in e , 1984 ) (T a b le 2 7 ) . P l a n t s , f rom Ovando a l s o a p p e a r to be more w in te r h a rdy th a n p l a n t s from H arlow ton . W in te r k i l l o f th e Ovando and H arlow ton p l a n t s , when grown a t B ozem an ,averaged 1-6 and 40 p e r c e n t r e s p e c t i v e ly . T a b le 27« The D e n s i ty an d Above G round B iom ass o f M a tu re S p o t t e d Knapweed P l a n t s G row ing a t H a rlow ton and Ovando, M ontana .^ P l a n t D e n s i ty B iom ass L o c a tio n p e r 0.5 m2 kg /h a H a r lo w to n 47 2100 Ovando 46 3264 I D ata were c o l l e c t e d on A ugust .4» 1982. S o i l f e r t i l i t y l e v e l s a t th e two s i t e s may e x p la in th e d i f f e r e n c e s i n p l a n t v i g o r . N i t r a t e l e v e l s i n t h e s u r f a c e f o o t a v e r a g e d 76 a n d 85 1 .8 ppm a n d p h o s p h o ru s l e v e l s w e re 26 a n d 6 ppm a t Ovando a n d H a r lo w ton , r e s p e c t i v e l y (T ab le 28). The e x tr em e ly low s o i l f e r t i l i t y l e v e l s a t t h e H a r lo w to n s i t e may be r e s p o n s i b l e f o r t h e d e c r e a s e d v ig o r e v id e n t i n th e s e p l a n t s . T a b le 28 . The Am ount o f N i t r o g e n , P h o s p h o r u s , a n d P o ta s s iu m i n t h e S u r fa c e F o o t o f S o i l from H arlow to n and Ovando, Montana. Locat i o n Nppm Pppm Kppm H arlow ton^ 1.8 6 .325 Ovando 76.0 26 294 Data f o r H a rlow to n i s b a sed on th e a v e ra g e o f com po s ite sam p le s ta k e n from b o th th e e a s t e r n and w e s te rn p o r t i o n o f th e s tu d y s i t e . T he m o re f a v o r a b l e g r o w in g c o n d i t i o n s e n c o u n te r e d i n t h e g re en h o u se and i n th e f i e l d s t u d i e s co nduc ted a t Bozeman in c r e a s e d th e v ig o r o f p l a n t s from H arlow ton . T h is in c r e a s e d v ig o r may have made th e p l a n t s m o re t o l e r a n t to 2 ,4 -D . L im i t e d u p ta k e o f 2 , 4-D by s p o t t e d knapweed may a l s o re d u c e th e p h y to to x ic e f f e c t s o f th e h e rb ic id e w i th in t h e p l a n t . T h e se r e s u l t s s u g g e s t t h a t u n d e r o p t im u m g r o w in g c o n d i t io n s , s p o t t e d knapweed i s som ew hat t o l e r a n t to 2 ,4-D . Summary F i e l d an d l a b o r a t o r y s t u d i e s w e re c o n d u c te d to m e a su re t h e r e s p o n s e o f tw o s t r a i n s o f s p o t t e d k n apw eed to 2 ,4 -D ° T h e re w as a s i g n i f i c a n t d i f f e r e n c e i n a v e ra g e b o l t h e ig h t , d a te o f f lo w e r in g , and a b o v e - g r o u n d b io m a s s f o r t h e tw o s t r a i n s . T h e re w as no d i f f e r e n c e b e tw e e n th e tw o s t r a i n s i n r e s p o n s e t o a p p l i c a t i o n o f 1 .12 a n d 2 .24 ) 8 6 k g /h a o f 2 ,4-D knapweed. U ptake and t r a n s l o c a t i o n o f 14A 2 ,4 -D was th e sam e i n b o th s t r a i n s o f s p o t t e d k n apw eed up to 8 d a y s f o l l o w i n g a p p l i c a t i o n . L e a f s u r f a c e p u b e s c e n c e a p p e a r s to i n t e r f e r w i t h t h e u p ta k e o f 2 ,4 -D . The am oun t o f ^^ rC 2 ,4 -D a b so rb ed i n t o e x c is e d le a v e s was 24 p e r c e n t i n no rm a l p u b e s c e n t l e a v e s com pared to 47 p e r c e n t when l e a f p u b escen ce was rem oved. The d i f f e r e n t i a l re sp o n se o f s p o t t e d knapweed to 2 ,4-D o b se rv ed i n f i e l d s t u d i e s a t Ovando an d H a r lo w to n may be due to d i f f e r e n c e s i n p l a n t v i g o r . When g row n a t t h e sam e l o c a t i o n u n d e r o p tim um g ro w in g c o n d i t io n s , p l a n t s from b o th l o c a t i o n s e x h ib i t e d t o le r a n c e to 2 ,4-D . 87 CHAPTER 7 SEED LONGEVITY OF SPOTTED KNAPWEED IN MONTANA SOILS A b s t r a c t S p o t te d knapweed ■( C en tau re a m acu lo sa Lam.) i s a s h o r t - l i v e d p e r e n n i a l t h a t r e p ro d u c e s by s e e d . Two e x p e r im en ts were e s ta b l i s h e d , in 1982 to d e te rm in e th e lo n g e v i ty o f v i a b i l i t y o f s p o t t e d knapweed s e e d s . R e s u l t s from th e f i r s t e x p e r im e n t , a seed b u r i a l s tu d y , showed t h a t l e s s th a n 50 p e r c e n t o f th e s e ed had g e rm in a te d 24 m onths f o l lo w in g b u r i a l . V i a b i l i t y o f th e rem a in in g se ed a v e ra g ed 94 p e r c e n t . Seed g e rm in a t io n r a t e and s e e d l in g v ig o r was s i g n i f i c a n t l y red u ced i n s e e d s b u r ie d a t th e Bozeman l o c a t i o n . The second s tu d y m easu red th e l o n g e v i ty o f seed v i a b i l i t y u n d e r n a t u r a l f i e l d c o n d i t io n s . A pp rox im a te ly 60 s e e d s p e r 0 .5 rem ained v i a b l e i n s o i l 26 m onths a f t e r se ed p ro d u c t io n had been s to p p e d . There . was no s i g n i f i c a n t d e c re a s e i n th e number o f v i a b l e s e ed s from A p r i l , 1983 to O c to b e r , 1984 . The p r o je c te d lo n g e v i ty o f v i a b i l i t y o f s p o t t e d knapweed seed i n n a t u r a l p o p u la t io n s i s 144 m on ths, assum ing a l i n e a r r a t e o f d e c l in e o f 48 p e r c e n t e v e ry 18 m on ths. I n t r o d u c t i o n S p o t te d Knapweed ( C en tau rea m acu lo sa ) c u r r e n t l y i n f e s t s o v e r 800 ,000 h e c ta r e s o f g r a z e a b le w oodland , r a n g e la n d , and p a s tu r e la n d in Montana (Maddox, 1979) • The p l a n t r e p ro d u c e s by s e e d , and i n d iv id u a l 88 p l a n t s can p roduce an a v e ra g e o f 1000 se ed s (S to ry , 1 9 7 6 ) . A pp rox im a te ly 90 p e r c e n t o f th e se ed p roduced by s p o t te d knapweed p l a n t s i s v i a b l e (S ch irm an , 1981 ) . The lo n g e v i ty o f v i a b i l i t y of. s p o t t e d knapweed se ed has n o t been d e te rm in e d . C h ico in e (1984) p r e d i c te d t h a t i t would tak e 60 to 75 months to c o m p le te ly e x h a u s t s o i l se ed r e s e r v e s u n d e r n a tu r a l c o n d i t io n s i n M ontana. P r e l im in a ry r e s u l t s r e p o r te d by Schirm an (1984) i n d i c a t e t h a t 40 p e r c e n t o f b u r ie d s p o t t e d knapweed se ed rem ain v i a b l e i n th e s o i l f o r a t l e a s t f i v e y e a r s . The l e n g th o f tim e seed rem ain v i a b l e i n s o i l i s im p o r ta n t when d e v e lo p in g h e r b ic id e t r e a tm e n t p rog ram s f o r s p o t t e d . knapweed c o n t r o l . O b je c tiv e s o f t h i s s tu d y were, to d e te rm in e th e l e n g th o f tim e s p o t t e d knapweed se ed rem a in v ia b le i n s o i l . t M a te r ia l s and Meth o d s Seed B u r ia l S tudy The seed b u r i a l s tu d y was co ndu c ted a t two l o c a t i o n s i n M ontana. S i t e 1 was l o c a t e d a t th e P o s t Agronomy Farm n e a r Bozeman, M ontana. The s o i l was c l a s s i f i e d a s Bozeman s i l t loam . S i t e 2 was lo c a te d on th e D ale F o lk vo rd Farm n e a r Three F o rk s , Montana on n a t i v e r a n g e . B oth s o i l s a r e deep and w e ll d r a in e d . M onthly tem p e ra tu re and p r e c i p i t a t i o n r e c o r d s f o r th e two s i t e s a r e shown i n Appendix D, (T a b le s 42 and 43.). I n p r e p a r a t i o n f o r th e b u r i a l s tu d y , f i f t y p o ly v in y l - c h lo r id e (PV C )• r i n g s ( 7 .6 cm d iam . by 2 .5 cm d ep th ) were c u t from PVC p ip e . Nylon window s c re e n (16 mesh) was cem ented to th e bo ttom o f e ach r i n g . The c o n ta in e r s were f i l l e d w ith s o i l g a th e re d from th e r e s p e c t iv e b u r i a l s i t e s . One hund red s p o t t e d knapweed s e e d s were p la c e d on th e i; 89 s u r f a c e o f th e s o i l i n e a ch c o n ta in e r and n y lo n window s c re e n was cem ented to th e to p s u r f a c e o f e a ch r i n g . The PVC c o n ta in e r s were b u r ie d 1 .5 cm deep a t b o th l o c a t io n s on Sep tem ber 22 , 1982 . The r i n g s were a r r a n g e d i n a random ized com p le te b lo ck d e s ig n . . F iv e se ed c o n ta in e r s were r e c o v e re d a t e a ch l o c a t io n on 1 1 -1 1 -8 2 , 4 -7 -8 3 , 5 -2 -8 3 , 5 -1 6 -8 3 , 6 -2 -8 3 , and 1 0 -1 0 -8 3 . The number o f s e ed s w h ich had g e rm in a te d w h ile b u r ie d , and th e p e rc e n ta g e o f v ia b le do rm an t seed was d e te rm in ed f o r e a ch c o l l e c t i o n d a te . B ecause o f low i n - f i e l d g e rm in a t io n and h ig h v i a b i l i t y o f th e do rm an t s e e d , th e s tu d y was r e v i s e d so t h a t th r e e c o n ta in e r s were r e c o v e re d once p e r y e a r a t e a ch l o c a t i o n a f t e r 1983» T h is m o d if ie d d e s ig n w i l l p e rm i t th e b u r i a l s tu d y to c o n tin u e th ro u g h 1989 and p ro v id e a b e t t e r i n d i c a t i o n o f s p o t t e d knapweed se ed lo n g e v i ty . C o n ta in e r s were r e c o v e re d O c tobe r 15, 1984. Seed was s e p a r a te d from th e s o i l by s c re e n in g th ro u g h a 1 0 .0 2 and 3 .1 0 mm ^ mesh s c r e e n . The rem a in in g se ed and s o i l m ix tu re was p la c e d on 0 .5 5 mm ^ s c re e n and g e n t ly washed w ith ru n n in g w a te r f o r th r e e m in u te s to remove th e f i n e s o i l p a r t i c l e s . S eeds were removed from th e rem a in in g m a te r i a l by h and . The number o f s e ed s t h a t g e rm in a te d d u r in g b u r i a l were d e te rm in ed by c o u n tin g empty se ed h u l l s . G e rm in a tio n t e s t s were p e rfo rm ed on 25 o f th e u n g e rm in a ted se ed from e a ch PVC r in g by f l o a t i n g them i n d i s t i l l e d w a te r f o r sev en d ay s a t 21 C. The p e r c e n t g e rm in a tio n o f seed was m easu red d a i l y o v e r th e sev en day p e r io d . A speed o f g e rm in a t io n in d ex was c a lc u la t e d u s in g th e method d e s c r ib e d by McGuire (1962 ) w here: 90 number o f g e rm in a te d s e e d l in g s Speed o f g e rm in a tio n = ---------------------------------------------------- day o f o b s e rv a t io n Com parisons o f s e e d l in g v ig o r were made betw een s e e d s from th e o r i g i n a l se ed l o t which were s to r e d in a d ry c o n d i t io n a t 21 C, and s e ed s r e c o v e re d from b o th l o c a t io n s i n May; 1983 and O c to b e r , 1984. S e e d lin g v ig o r t e s t s were p e rfo rm ed on g e rm in a te d se ed by p la c in g them "V i n 16 X 15 X 4 cm g e rm in a t io n boxes f i t t e d w ith m o is ten ed b l o t t e r p a p e r . The boxes were p la c e d on an 85 s l a n t i n a d a rk g e rm in a to r a t ■ i\ 20 C. R a d ic le l e n g th was m easured d a i l y f o r 6 d a y s . Speed o f e lo n g a t io n in d ex was c a l c u l a t e d u s in g th e fo rm u la d e s c r ib e d by C a r le to n e t a l . (1 9 6 8 ): change i n r a d i c l e l e n g th Speed o f e lo n g a t io n = ------------------------------------------- day o f o b s e rv a t io n D ata were a n a ly z e d by a n a ly s i s o f v a r i a n c e . C u l tu r a l P r a c t i c e S tudy The lo n g e v i ty o f v i a b i l i t y o f a n a tu r a l s o i l r e s e r v e o f s p o t t e d knapweed seed was s tu d i e d a t two l o c a t i o n s i n M ontana. The s tu d y was e s t a b l i s h e d a t th e same s i t e s ( n e a r H arlow ton and Ovando) a s th e p ic lo ram r a t e s tu d y i n C hap te r 5 . C l im a tic c o n d i t io n s o f th e s tu d y a r e a s a r e shown i n Appendix D, (T a b le s 36 and 37 j). F iv e t r e a tm e n ts were a p p l i e d to p l o t s a t e a ch s i t e to d e te rm in e t h e i r e f f e c t on th e lo n g e v i ty o f se ed v i a b i l i t y . T re a tm en ts in c lu d e d r o l l i n g , h a rrow in g , b u rn in g , mowing, a 2 ,4 -D a p p l i c a t i o n , and an u n t r e a te d c o n t r o l . T re a tm en ts were a p p l i e d i n 1982 a s d e s c r ib e d by C h ico in e (1 9 8 4 ) . P l o t s were a r r a n g e d in a s p l i t b lo c k d e s ig n w ith th r e e r e p l i c a t i o n s p e r t r e a tm e n t . A ll p l o t s e x c e p t th e u n t r e a te d 91 c o n t r o l were sp ray ed a n n u a l ly i n June w ith 2 .2 4 k g /h a o f 2 ,4 -D to p r e v e n t se ed p ro d u c t io n . The p o p u la t io n o f m atu re and s e e d l in g s p o t te d knapweed p l a n t s was m easured by t a k in g p l a n t d e n s i ty c o u n ts in s ix random ly s e le c te d 0 .0 9 m2 l o c a t i o n s i n e a ch p l o t i n J u n e , 1983 and 1984 p r i o r to th e 2 ,4 -D a p p l i c a t i o n . The amount o f u n g e rm in a te d seed rem a in in g in s o i l was m easu red by t a k in g s ix 3 .6 cm^ d iam e te r s o i l c o re s (to . a d e p th o f 7 .6 cm) w i th in e a ch p l o t w ith a t a p e r e d t u l i p b u lb p l a n t e r in A p r i l and O c to b e r , i n b o th 1983 and 1984« The l o c a t io n o f e a ch s o i l c o re was s e l e c t e d random ly , how ever, i f th e random lo c a t io n cho sen f o r a sample s i t e was on a r o d e n t bu rrow , a new l o c a t io n was s e l e c t e d . R oden ts a r e b e l i e v e d to consume s p o t t e d knapweed s e e d s and may be a so u rc e o f se ed c o n tam in a t io n on th e p l o t a r e a s ( p e r s o n a l o b s e rv a t io n ; S i lv e r to w n , 1 9 8 2 ) . S o i l was s e p a r a te d from th e seed th ro u g h a s e r i e s o f s c r e e n in g , w ash ing , and a i r c le a n in g s t e p s ( C h ic o in e ,, 1 9 8 4 ) . Seed from e a ch c o re were f l o a t e d on d i s t i l l e d w a te r a t 21 C f o r sev en d a y s . The number o f g e rm in a te d s p o t t e d knapweed se ed were co un ted d a i l y . R e s u l t s and D is c u s s io n S eed . B u r ia l S tudy Seed re c o v e ry from b u r ie d s o i l c o re s av e rag ed 99 and 98 p e r c e n t f o r Bozeman and Three F o rk s , r e s p e c t i v e ly (T ab le 2 9 ) . I n - f i e l d g e rm in a t io n o f seed a v e ra g ed 20 p e r c e n t a t Bozeman and 45 p e r c e n t a t T hree F o rk s 24 months a f t e r b u r i a l (T ab le 3 0 ) . The number o f s e ed s g e rm in a te d a f t e r 24 months was s i g n i f i c a n t l y g r e a t e r th a n a t 2 .5 m onths a f t e r b u r i a l . 92 T ab le 29 . R ecovery o f B u ried S p o tte d Knapweed Seed Sam ples in th e Seed B u r ia l S tudy E s ta b l i s h e d on S e p t . 21 , 1982 a t Bozeman' and Three F o rk s . Months o f B u r ia l Seed Bozeman Recovery (%) Three F o rk s 2 .5 100a1 100a 7 .0 99a TOOa 8 .0 100a 98a 8 .5 99a ,99a 9 .0 . 98a 98a 12 .5 97a 95a 2 4 .0 100a 99a X 99 98 I Means w i th in a column fo llow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5% l e v e l u s in g th e LSD t e s t While i n - f i e l d g e rm in a t io n re d u c e d seed p o p u la t io n s a f t e r two y e a r s , more th a n 50 p e r c e n t o f seed d id n o t g e rm in a te i n th e s o i l . A h ig h p e rc e n ta g e o f g e rm in a t io n was m easu red i n s e v e r a l PVC c o n ta in e r s a t Three F o rk s w hich was c au sed by m ic r o - c l im a t ic c o n d i t io n s c r e a te d d u r in g th e b u r i a l o f th e PVC r in g s ( C h ic o in e , 1984)• The r in g s s e t t l e d fo l lo w in g b u r i a l c r e a t i n g a d e p r e s s io n i n th e s o i l w hich c o l l e c t e d > p r e c i p i t a t i o n . The in c r e a s e d m o is tu re may have s t im u la te d h ig h e r th an no rm al l e v e l s o f g e rm in a t io n . V i a b l i l i y o f th e u n g e rm in a ted s e e d s was 96 and 92 p e r c e n t a t Bozeman and T hree F o rk s r e s p e c t i v e ly (T ab le 3 0 ) . There was no s i g n i f i c a n t d i f f e r e n c e i n v i a b i l i t y be tw een b u r ie d and u n b u r ie d s e e d . The a b i l i t y o f th e s e e d s to g e rm in a te in a f a v o r a b le env iro nm en t i n d i c a t e s t h a t e n fo rc e d dormancy r a t h e r th a n in n a te o r in d u ced dormancy may be r e s p o n s ib le f o r l a c k o f g e rm in a t io n (Cook, 1 9 8 0 ) . T here was no s i g n i f i c a n t d i f f e r e n c e in sp eed o f g e rm in a t io n betw een seed b u r ie d f o r 24 months a t Three F o rk s and th e u n b u r ie d 93 c o n t r o l . However, se ed b u r ie d 24 months a t Bozeman g e rm in a te d a t a s i g n i f i c a n t l y s low e r r a t e th a n seed b u r ie d a t Three F o rk s o r seed from th e o r i g i n a l s e ed l o t which were s to r e d a t 21 C. There was. no d i f f e r e n c e i n t o t a l p e r c e n t g e rm in a t io n betw een th e th r e e seed l o t s a f t e r f iv e , d ay s (F ig u re 1 3 ) . T ab le 3 0 . P e r c e n t G e rm in a tio n D uring th e B u r ia l P e r io d , and th e V i a b i l i t y o f Dormant S p o t te d Knapweed Seed in th e Seed B u r ia l S tudy E s t a b l i s h e d S e p t . 21 , 1982 a t Bozeman and Three F o rk s . Months o f B u r ia l P e r c e n t G e rm in a tio n D uring B u r ia l Bozeman Three F o rk s P e r c e n t V i a b i l i t y U ngerm ina ted Seed Bozeman Three F o rks 2 .5 1a 1 1a 99a 99ab 7 -0 20bc 13a 98ab 98ab 8 .0 13ab 7a 97ab 100a 8 .5 17bc 8a 98ab 99ab 9 .0 12ab 7a 87c 95 be 12 .5 1 la b 34b 91'be 95bc 2 4 .0 20bc 45b ■ 96ab 92c u n b u r ie d — — 99a 99ab ^Means w i th in a column fo llow ed by th e same l e t t e r a r e ,no t s i g n i f i c a n t l y d i f f e r e n t a t th e 5% l e v e l u s in g th e LSD t e s t . S e e d lin g v ig o r ( e x p re s s e d a s sp eed o f r a d i c l e e lo n g a t io n ) was th e same b e tw een s e e d s b u r ie d f o r 9 and 24 months a t Three F o rk s and th e u n b u r ie d c o n t r o l . R a d ic le e lo n g a t io n was s low e r w ith s e e d s b u r ie d f o r 9 and 24 months a t Bozeman compared to e i t h e r T hree F o rk s o r th e u n b u r ie d c o n t r o l ( F ig u re 1 4 ) . D e c lin e in s e e d l in g v ig o r i s e x p re s s e d by, sp eed o f r a d i c l e e lo n g a t io n and sp eed o f g e rm in a t io n in d e x e s shown i n T ab le 31 . Speed o f g e rm in a t io n in d e x e s were n o t c a l c u l a t e d f o r seed b u r ie d a t Bozeman P er ce n t G er m in at io n 94 lOO-i i T h r e e Fo rks 2 Con t r o l SB o z eman D a y s A f t e r Imbi t i on F ig u re 13 . P e r c e n t G e rm in a tio n o f Seed B u ried f o r 24 Months a t T hree F o rk s and Bozeman and th e U nburied C o n tro l . P o in t in th e same d a te fo llow ed by th e same l e t t e r a re n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . 95 Thre e Forks 9 mon th s 2 4 mon th s 0 3 Contro l B o z em a n Qmonths 2 4 mon th s D a y s A f t e r Imbi t ion F ig u re 14- R a te o f R a d ic le E lo n g a tio n in Seeds B u ried f o r 9 and 24 M on th s a t B ozem an an d T h re e F o r k s , and th e U nburied C o n tro l. ■1 P o i n t s i n t h e sam e d a t e f o l l o w e d by th e sam e l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t t h e 5 p e r c e n t l e v e l u s in g t h e LSD t e s t . f o r 9 m o n th s b e c a u s e o f th e s m a l l am o u n t o f s e e d s a v e d i n 1983 . The l o w e r in d e x v a l u e s f o r s e e d b u r i e d a t B ozem an c om p a red t o s e e d f rom T h re e F o rk s m ay be due to a c c e l e r a t e d a g in g o f t h e s e e d . V i s u a l symptom s o f a g in g in c lu d e d d e t e r i o r a t i o n o f th e pappus and th e m ic ro - p i l o r p lu g . The a c c e l e r a t e d a g in g o f th e se ed a t Bozeman may be due to i n c r e a s e d m ic ro b e a n d f u n g i p o p u l a t i o n s a s a r e s u l t o f h i g h e r p r e c i p i t a t i o n (Bew ley and B lack , 1978) (F ig u re 15). 96 , - T a b le 31 • S p e ed o f G e rm in a t io n an d S p e ed o f E l o n g a t i o n In d e x N um bers f o r Seed R ecovered From Bozeman and T h ree F o rk s 24 Months A f te r B u r i a l . L o c a tio n Ind ex Numbers Speed o f G e rm in a tio n Speed o f E lo n g a tio n 1983 1984 1983 1984 Bozeman — 12.9a 1 0 .54a 0 .3 1 a Three F o rk s - 22.5b 0.89b 0.98b U nburied — 23.0b 0 .9 1b 0 .91b ^M e an s w i t h i n a c o lu m n f o l l o w e d by t h e s am e l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 % l e v e l u s in g th e LSD t e s t . C u l tu r a l P r a c t i c e S tudy The n um be r o f v i a b l e s e e d r e m a in i n g i n s o i l d e c r e a s e d 91 a n d 88 p e r c e n t a t Ovando a n d H a r l o w ton r e s p e c t i v e l y i n a 28 m on th p e r i o d f o l l o w i n g th e t e r m i n a t i o n o f s e e d p r o d u c t i o n ( F i g u r e s 16 and 17 ; A p p en d ix D, T a b le s 44 and 4 5 ) . S eed r e s e r v e s d e c l i n e d 87 p e r c e n t a t Ovando a n d 72 p e r c e n t a t H a r lo w to n th e f i r s t 10 m o n th s a f t e r s e e d p ro d u c t io n was s to p p ed . However, th e r a t e o f d e c l in e a v e rag ed o n ly 47 p e r c e n t t h e f o l l o w i n g 18 m on th s a t b o th l o c a t i o n s . An a v e r a g e o f 34 a n d 97 v i a b l e s e e d s r e m a in e d p e r 0 .5 m e te r s q u a re , a t Ovando an d 97 F ig u re 15- P h o to g rap h s Showing th e E f f e c t o f Aging on Bozeman Seed (Top) Compared to th e U nbu ried C o n tro l (B o ttom ). 98 1 Harrow 2 Roll 3 Burn 4 Mow 5 Spray Check 6 Control Mon t h s Wi t h ou t S e e d P r o d u c t i o n F ig u re 16 . Changes i n S p o tte d Knapweed Seed R e se rv e s w ith V a rio u s C u l tu r a l P r a c t i c e s from 0 to 28 Months A f te r Seed P ro d u c tio n Was S topped a t Ovando I I P o in ts in th e same month fo llow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . 99 1 H a r r o w 2 Rol l 3 Bur n 4 Mow 5 S p r a y C h e c k 6 Control Months Wi thout S e e d P roduc t i on F ig u re 17» Changes in S p o tte d Knapweed Seed R e se rv e s w ith V a rio u s C u l tu r a l P r a c t i c e s from 0 to 28 Months A f te r Seed P ro d u c tio n Was S topped a t H arlow ton ^ . "* P o in ts i n th e same month fo llow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . 100 H arlow to n , r e s p e c t i v e ly , 28 m onths a f t e r se ed p ro d u c t io n was h a l t e d . There was a s i g n i f i c a n t d e c l in e o f v i a b l e s e e d s from A p r i l , 1983 to O c to b e r , 1984 a t H a r lo w ton . However, no d e c l in e i n v i a b l e s e ed s was m easu red a t Ovando. The c u l t u r a l p r a c t i c e s t e s t e d which were d e s ig n e d to im prove se ed to s o i l c o n ta c t d id n o t in f lu e n c e th e r a t e o f d e c l in e o f s e ed r e s e r v e s . F ig u re 18 shows th e d e c l in e i n se ed r e s e r v e s f o r b o th l o c a t io n s and a l l c u l t u r a l p r a c t i c e s com bined . F o llow ing th e i n i t i a l r a p id d e c l in e i n s o i l se ed r e s e r v e s , th e number o f v i a b l e seed d e c l in e d s lo w ly . T h is r e s p o n s e s u g g e s ts t h a t a p o r t i o n o f s p o t t e d knapweed seed i n th e s o i l i s r e g u la te d by e n fo rc e d dorm ancy. The m echanism s t h a t p r e v e n t s p o t t e d knapweed se ed from g e rm in a t in g u nd e r norm al f i e l d c o n d i t io n s a p p e a r to be im p o r ta n t i n e x te n d in g th e lo n g e v i ty o f seed in th e s o i l . The g ra d u a l d e c l in e o f s e ed in th e s o i l may be cau sed by g e rm in a t io n o f th e se ed when e n v iro nm en ta l c o n d i t io n s a r e o p t im a l . O th e r f a c t o r s w hich c o u ld red u ce s o i l se ed r e s e r v e s in c lu d e p r e d a t io n o r s e n e s c e n s e (R ado sev ich and H o l t , 1 9 8 4 ) . The lo ng te rm r a t e o f d e c l in e o f v i a b l e s p o t t e d knapweed seed i n s o i l can be e s t im a te d by c a l c u l a t i n g th e r a t e o f d e c l in e from A p r i l , 1983 to O c to b e r , 1984« T h is p r o v id e s a more a c c u r a te p r e d i c t i o n o f s e ed lo n g e v i ty th a n was made by C h ico in e (1984) s in c e i t e l im in a te s th e i n i t i a l r a p id d e c l in e i n seed r e s e r v e s which o c c u rre d betw een J u n e , 1982 and A p r i l , 1983« The s o i l r e s e r v e o f v ia b le seed d e c re a s e d 49 and 45 p e r c e n t a t H arlow ton and Ovando r e s p e c t i v e ly from A p r i l , 1983 to O c to b e r , 1984« Assuming a c o n s ta n t r a t e o f d e c l i n e , i t w i l l ta k e 144 101 Control T res t ed 0 - - Months Without S e e d Product ion F ig u re 18 . The D e c lin e o f V iab le S p o t te d Knapweed Seed R e se rv e s from 0 to 28 Months A f te r Seed P ro d u c tio n was S to p p ed . ^ "I Data a r e f o r a v e ra g e s o f a l l c u l t u r a l p r a c t i c e s from H arlow ton and Ovando com bined . 2 P o in ts in th e same month fo llow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . 102 months to re d u c e th e number o f v i a b l e seed r e s e r v e s to l e s s th an one se ed p e r 0 .5 m e te r s q u a re a t b o th l o c a t i o n s (T ab le 3 2 ) . The p r e d i c te d r a t e o f d e c l in e (T ab le 32) d o e s n o t tak e i n t o a c c o u n t th e r e d u c t io n i n seed v ig o r o b se rv ed i n th e b u r i a l s tu d y (T ab le 3 1 ) . A d e c l in e i n s e ed and s e e d l in g v ig o r co u ld h in d e r b o th seed g e rm in a t io n and s e e d l in g e s t a b l i s h m e n t . The breakdown o f dormancy" mechanism w i th in th e se ed co u ld a l s o r e s u l t i n u n s u c c e s s fu l g e rm in a t io n and d e a th (R ado sev ich and H o l t , 1 9 8 4 ) . The i n a b i l i t y o f v ia b le s e e d s to g e rm in a te and e s t a b l i s h would d e c re a s e th e e f f e c t i v e l e n g th o f tim e t h a t th e p o p u la t io n co u ld r e e s t a b l i s h from endogenous s o i l se ed r e s e r v e s . T ab le 3 2 . The P r e d ic te d R ate o f D e c lin e o f S p o tte d Knapweed Seed Based on th e R ate o f D e c lin e M easured from A p r i l , 1983 to O c to b e r , 1984 a t H arlow ton and Ovando. Months A f te r Seed P ro d u c tio n i s S topped Number o f "Viable H arlow ton Seed p e r 0 .5 m ^ Ovando 10 186 61 28 95 34 36 48 19 54 24 10 72 12 6 90 6 3 108 3 1 .7 126 1 .5 1 144 <1 <1 S in c e c u l t u r a l p r a c t i c e s d id n o t in f lu e n c e s p o t t e d knapweed s e e d l in g o r m a tu re p l a n t d e n s i t y , d a ta was a v e ra g ed f o r a l l t r e a t e d p l o t s . S p o t te d knapweed s e e d l in g d e n s i t i e s d e c re a s e d from Ju n e , ' 1983 to J u n e , 1984 (T ab le 3 3 ) . An a v e ra g e o f one and tw e lv e p e r c e n t o f th e 103 v ia b l e se ed i n th e t r e a t e d p l o t s a t H arlow ton and Ovando r e s p e c t i v e ly g e rm in a te d and became e s t a b l i s h e d s e e d l in g s i n 1984. The d e c l in e i n s e e d l in g e s ta b l i s h m e n t may r e f l e c t e i t h e r a d e c re a s e in s e e d l in g v ig o r o r a change i n f a v o r a b i l i t y o f e n v iro nm en ta l c o n d i t io n s from ■ 1983 to 1984 . T here was no d i f f e r e n c e in m atu re p l a n t d e n s i ty from 1983 to 1984. T ab le 3 3 . The P l a n t D e n s i ty o f S p o t te d Knapweed S e e d l in g s in T re a te d and C o n tro l P l o t s in June 1983 and June 1984 a t H arlow ton and Ovando. H arlow ton Ovando Year c o n t r o l t r e a t e d c o n t r o l t r e a t e d 1983 489a1 22a 933a 24a 1984 2?2a 1b 733a 4b Means w i th in a column fo llow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5% l e v e l u s in g th e LSD t e s t The number o f v i a b l e seed (650 p e r 0 .5 m^) i n th e c o n t r o l p l o t i n 1984 a t Ovando i s a p p ro x im a te ly th e same a s th e number o f e s t a b l i s h e d s e e d l in g s (733 p e r 0 .5 m ^). T h is s u g g e s ts a s t a t i c p o p u la t io n , where d e p o s i t s o f se ed from se ed p ro d u c t io n and d i s p e r s a l i s a b o u t e q u a l ,to w ith d raw a ls from th e s o i l se ed r e s e r v e by g e rm in a t io n . T h is s t a t i c p o p u la t io n i s n o t o b se rv ed in H arlow ton where th e am ount o f v ia b le seed i n th e s o i l ex ceed th e number o f s e e d l in g s e s t a b l i s h e d i n 1984 . E nv iro nm en ta l c o n d i t io n s a t H arlow ton may n o t have been optimum f o r s e e d l in g e s ta b l i s h m e n t . 104 Summary S p o t te d knapweed s e e d s w hich do n o t g e rm in a te rem a in v i a b l e in s o i l f o r 24 m onths f o l lo w in g b u r i a l . F i e ld g e rm in a t io n o f b u r ie d seed was l e s s th a n 50 p e r c e n t and th e v i a b i l i t y o f u n g e rm in a ted seed was, 94 p e r c e n t . Speed o f g e rm in a t io n and sp eed o f r a d i c l e e lo n g a t io n in d e x e s were low e r i n se ed b u r ie d a t Bozeman th a n seed b u r ie d a t T hree F o rk s o r u n b u r ie d s e e d . • T h is s u g g e s ts a d e c l in e i n seed v ig o r f o r s e ed s b u r ie d a t Bozeman. The d e c re a s e i n seed v ig o r may i n d i c a t e t h a t a c c e l e r a t e d a g in g o f seed h a s o c c u r re d a s a r e s u l t o f ' h ig h e r p r e c i p i t a t i o n a t Bozeman. The number o f v i a b l e seed i n n a t u r a l se ed p o p u la t io n s d e c re a s e d 48 p e r c e n t from A p r i l , 1983 to O c to b e r , 1984« L ess th an 15 p e r c e n t o f th e v i a b l e se ed i n s o i l g e rm in a te d and became e s t a b l i s h e d i n 1984• V a rio u s c u l t u r a l p r a c t i c e s d e s ig n ed to i n c r e a s e seed to s o i l c o n ta c t had no e f f e c t on p e r c e n t se ed g e rm in a t io n o r s e e d l in g e s ta b l i s h m e n t . A pp rox im a te ly 25 p e r c e n t o f s p o t t e d knapweed seed in n a tu r a l p o p u la t io n s a p p e a r s to be r e g u la te d by e n fo rc e d dorm ancy. Dormancy mechanism s a r e im p o r ta n t i n e x te n d in g th e lo n g e v i ty o f v i a b i l i t y o f s p o t t e d knapweed se ed i n s o i l . The p r o je c te d lo n g e v i ty o f v i a b i l i t y o f s e ed in n a tu r a l p o p u la t io n s i s 144 m on ths , ' a ssum ing a l i n e a r r a t e o f d e c l in e o f 48 p e r c e n t e v e ry 18 m on th s . However, r e d u c t io n s i n seed and s e e d l in g v ig o r from n a t u r a l a g in g c o u ld d e c re a s e th e l e n t h o f tim e r e q u i r e d to s to p s e e d l in g e s ta b l i s h m e n t on a s i t e . These s tu d i e s w i l l be c o n tin u e d d e te rm in e . th e e x a c t p e r io d o f lo n g e v i ty o f v i a b i l i t y o f s p o t t e d knapweed s e e d s i n s o i l 105 SUMMARY Leafy sp u rg e and s p o t t e d knapweed a r e th e two m ajo r weed p rob lem s on ra n g e la n d i n M ontana. E x te n s io n and r e s e a r c h p rogram s were i n i t i a t e d i n an e f f o r t to s to p th e s p re a d o f th e two weeds. They in c lu d e d : an e d u c a t io n a l p rogram on l e a f y sp u rg e and s p o t t e d knapweed, th e e f f e c t o f red u c ed r a t e s o f p ic lo ram and p ic lo ram / 2 , 4-D c om b in a tio n s on c o n t r o l o f s p o t t e d knapweed, th e e f f e c t o f 2 , 4-D on two s t r a i n s o f s p o t t e d knapweed, and th e lo n g e v i ty o f v i a b i l i t y o f s p o t t e d knapweed seed i n Montana s o i l s . N e w s le t t e r s , h e r b ic id e d em o n s tra t io n p l o t s , f i e l d t o u r s , and a ransom program were e f f e c t i v e i n i n c r e a s in g p u b l ic aw aren ess ' and c o n t r o l o f l e a f y sp u rg e and s p o t t e d knapweed i n M ontana. The e f f e c t i v e n e s s o f th e o v e r a l l p rogram was enhanced by u t i l i z i n g an i n t e g r a t e d a p p ro a ch w hich in v o lv e d r e s e a r c h e r s , e x te n s io n s p e c i a l i s t s , and f e d e r a l and s t a t e e n t i t i e s . P ic lo ram i s th e m ost e f f e c t i v e h e rb ic id e f o r c o n t r o l l i n g s p o t t e d knapweed. P ic lo ram r a t e s a s_ low a s 0 .1 4 k g /h a w i l l p ro v id e up to two y e a r s o f c o n t r o l o f m a tu re s p o t t e d knapweed p l a n t s . The r e s i d u a l p e r io d o f p ic lo ram d e te rm in e s th e l e n g th o f c o n t r o l o f s p o t t e d knapweed. The a d d i t i o n o f 2 , 4-D to p ic lo ram does n o t s i g n i f i c a n t l y im prove c o n t r o l o v e r p ic lo ram a lo n e . The rem oval o f s p o t t e d knapweed from th e p l a n t community r e s u l t s i n an i n c r e a s e i n g r a s s p ro d u c t io n o f 200 to 770 p e r c e n t . 106 D i f f e r e n t i a l t o l e r a n c e o f s p o t t e d knapweed to 2 ,4 -D o b se rv ed i n f i e l d t r i a l s a t Ovando and H arlow ton was ex am ined . There was no d i f f e r e n c e i n r e s p o n s e to 2 ,4 -D be tw een p l a n t s from b o th l o c a t io n s when grown u n d e r i d e n t i c a l c o n d i t io n s . The to le r a n c e o f s p o t t e d knapweed to 2 ,4 -D o b se rv ed i n th e i n i t i a l f i e l d s t u d i e s was p ro b a b ly due to d i f f e r e n c e s i n p l a n t v ig o r r a t h e r th a n d i f f e r e n c e s in u p tak e o r movement o f th e h e r b i c i d e . S p o t te d knapweed se ed rem a in v i a b l e i n th e s o i l f o r a t l e a s t 28 m onths u n d e r b u r ie d and n a t u r a l c o n d i t i o n s . L ess th a n 50 p e r c e n t o f th e b u r ie d se ed had g e rm in a te d 24 months f o l lo w in g b u r i a l . There was an a v e ra g e o f 65 v i a b l e s e e d s p e r 0 .5 m ^ rem a in in g i n a n a tu r a l seed p o p u la t io n 28 m onths a f t e r se ed p ro d u c t io n was s to p p e d . 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J . Range M gt.34 :45 -47« S ch irm an , R o land . 1984 . S e e d lin g e s ta b l i s h m e n t and se ed p ro d u c t io n o f d i f f u s e and s p o t t e d knapweed, p . 7 -1 0 I n P ro c : Knapweed Symposium. P l a n t and S o i l D ep t, and Coop. E x t . S e rv . Montana S ta te U n iv . , B u l l . 1315. S c i f r e s , C . J . , R .R . Hahn, J . D iaz -C o lon and M.G. M e rk le . 1971. P ic lo ram p e r s i s t e n c e in s e m i- a r id r a n g e la n d s o i l s and w a te r . Weed S c ie n c e 19 :381-384« 114 Sexsm it h , J . J . 1964« M o rpho lo g ica l and h e rb ic id e s u s c e p t i b i l i t y d i f f e r e n c e s among s t r a i n s o f h o a ry c r e s s . Weeds. 1 2 :1 9 -2 2 . S i lv e r to w n , J o n a th a n W. 1982. I n t r o d u c t i o n to p l a n t p o p u la t io n e c o lo g y . Longman I n c . , New York. S k o s s , J .D . 1955 . S t r u c tu r e and c om po s itio n o f p l a n t c u t i c l e i n r e l a t i o n to e n v iro nm en ta l f a c t o r s and p e rm e a b i l i t y . B o t. G az. 1 1 7 :5 5 -7 2 . S to r y , J .M . 1976 . A s tu d y o f U ropho ra a f f i n i s (D ip t e r a :T e p h r i t id a e ) r e l e a s e d on s p o t t e d knapweed i n w e s te rn M ontana. M. S c . t h e s i s , Montana S t a t e U n iv . W atson, A.K. and A .J . Renney. 1974* The b io lo g y o f C anad ian w eeds. 6 . C en tau re a d i f f u s a and m acu lo sa . Can J . P l a n t S c i . 5 4 :6 8 7 -7 01 . W a tte n b a rg e r , D.W ., W.S. B e l l e s , and G.A. L ee . 1980. E f f e c t s o f h e r b i c id e s on th e c o n t r o l o f s p o t t e d knapweed i n r a n g e la n d s . W est. S o c . R es . P ro g . R e p t . p . 63- 64 . W h itehead , C.W. and C.M. S w itz e r . 1963 . The d i f f e r e n t i a l re sp o n se o f s t r a i n s o f w ild c a r r o t to 2 ,4 -D and r e l a t e d h e r b i c id e s . Can. J . P l a n t S c i . 4 3 :2 5 5 -2 5 9 . W h itw o rth , J.W . 1964 . The r e a c t i o n s o f s t r a i n s o f f i e l d bindweed to 2 ,4 -D . Weeds. 1 2 :1 6 7 . W h itw o rth , J.W . and T .J . M uzik. 1967 . D i f f e r e n t i a l r e s p o n s e o f s e l e c t e d c lo n e s o f b indw eed to 2 ,4 -D . Weeds 1 5 :2 75 -2 79 . W it t , E ldon E. 1968 . E x p e r im en ta l p l o t s , a key to e f f e c t i v e a d u l t e d u c a t io n . Ag. E d u c a tio n M agazine 4 1 :3 2 -3 3 . Y oungson, C .R ., C .A .I . G o rin g , R.W. M e ik le , H.H. S c o t t and J .D . G r i f f i t h . 1967. F a c to r s i n f lu e n c in g th e d e com po s itio n o f Tordon h e r b i c id e i n s o i l s . Down to E a r th 2 3 :3 -1 1 . 115 APPENDICES 116 APPENDIX A NEWSLETTERS 117 Leafy Spurge News PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN. MONTANA 59717 Volume IV May 1983 Issue 2 Newsletter continues with a new ed itor ! Hi, I'm the new ed i to r o f the Leafy Spurge Newsletter . My name i s C e le s t in e Lacey and I j u s t s tar ted working on a Master's degree in Weed Science with Dr. Pete Fay a t Montana S ta te Un ivers i ty . A large part o f my work w i l l invo lve a lea fy spurge ex tens ion program. Bruce Maxwell i s continuing to work on h is Master's , but w i l l concentrate h is e f f o r t s on le a fy spurge research. We appreciate the e x c e l l e n t job that Bruce did ed it in g the n ew s le t te r , and w i l l keep you updated on the progress o f h is research. Maw----- w i t h l e a f / s o u r c e i t ' s n o t a lways what you sp r ay but how you Iirayl J u n e 2 0 . 1 9 8 3 J u n e 2 1 . 1 9 8 3 8 : 0 0 a n 8 : 4 0 a m 9 : 0 0 a m 1 0 : 0 0 a m L e a f y S p u r g e S y m p o s i u m S u n d a n c e , W y o m i n g J u n e 2 1 - 2 2 , 1 9 8 3 5 : 0 0 - 8 : 0 0 p m , R c g i s c r a t i o n , L o b b y o f t h e B e a r L o d g e C o u n t y C o u r t h o u s e B a s e m e n t F u t u r e d i r e c t i o n o f l e a f y s p u r g e r e s e a r c h i n G r e a t P l a i n s a r e a . D r . D o n A n d e r s o n - A d m i n i s t r a t i v e A d v i s o r o f G r e a t P l a i n s A g r i c u l t u r a l C o u n c i l . F u t u r e d i r e c t i o n o f l e a f y s p u r g e r e s e a r c h f r o m a U n i v e r s i t y v i e w p o i n t . D r . H a r o l d ' l u m a - D e a n . C o l l e g e o f A g r i c u l t u r e , U n i v e r s i t y o f W y o m i n g . S t a t e l e a f y s p u r g e p r o g r a m f r o m a l e g i s l a t i v e v i e w p o i n t . W y o m i n g S t a t e S e n a t o r . S t a t e l e a f y s p u r g e p r o g r a m f r o m S t a t e W e e d a n d P e s t C o o r d i n a t o r v i e w p o i n t . G e o r g e H l t t l e - W e e d a n d P e s t C o o r d i n a t o r - W y o m i n g S t a t e D e p a r t m e n t o f A g r i c u l t u r e . C O F F E E B R E A K S t a t e l e a f y s p u r g e p r o g r a m f r o m a W e e d a n d P e s t S u p e r v i s o r ' s v i e w p o i n t . B o b B e n j a m i n - W e e d a n d P e s t S u p e r v i s o r , S h e r i d a n . LEAFY SPURGE SYMPOSIUM The most important spurge event o f the year w i l l be held in Sundance, WY on June 21 and 22, 1983. There w i l l be something on the program fo r anyone in t e r ­ es ted in l e a f y spurge. Speakers w il l include researchers , weed superv isors , and ranchers from Colorado, Wyoming, North Dakota, South Dakota, Montana, Maryland, and C a l i fo rn ia . A d e ta i led agenda o f the symposium fo l low s . 1 0 : 2 0 a m S t a t e l e a f y s p u r g e p r o g r a m f r o m a r a n c h e r ' s v i e w p o i n t . J e s s D r l s k i l l - R a n c h e r . H u l e t c . 1 0 : 4 0 a m L e a f y s p u r g e p r o g r a m f r o m W e e d a n d P e s t b o a r d m e m b e r ' s v i e w p o i n t . J o h n D o r r a n c e - b o a r d M e m b e r . C r o o k C o u n t v . 1 1 : 0 0 a m R e s e a r c h R e p o r t s , N o r t h D a k o t a . C a l M e s s e r s m i t l i - C h a i r m a n . 1 1 : 4 5 a m L U N C H A f t e r n o o n - J u n e 2 1 , 1 9 8 3 1 : 1 5 pm Mon ta n a R e s e a r c h R e p o r t s - P e t e r Fa vc - C h a i rm a n . N u t r i ­ t i o n a l v a l u e o f l e a f y s p u r g e a s a l o r a g e compon en t f o r ewes an d l am b s . S . 3 . B a r t : , K. M, H u s ta d and L . L . A v r e s . SEE YOU IN SUNDANCE! I : 3 0 p m H e r b i c i d e a p p l i c a t i o n a c c e s s o r i e s f o r a l l t e r r a i n v e h i c l e s . L e e C o b l e , B r u c e F U x w e l l a n d P e t e r F a y e . 118 J u n e 2 1 , 1 9 8 3 1 : 4 5 p m U p d a t e o n l e a f y s p u r g e r e s e a r c h a t M o n t a n a S t a t e U n i v e r ­ s i t y . B r u c e M a x w e l l a n d P e t e r F a y e . X MONTANA 2 : 0 0 p m 2 : 1 5 p m 2 : 3 0 p m 2 : 4 5 p a 3 : 0 0 p m 3 : 1 5 p m 3 : 3 0 p m 3 : 4 5 p m 4 : 0 0 p m 4 : 1 5 p m 4 : 3 0 p m 5 : 0 0 p m 5 : 1 5 p m 6 : 0 0 p m L e a f y s p u r g e a w a r e n e s s p r o g r a m s i n M o n t a n a . P a r t I I . C e l e s t l a n L a c y a n d P e t e r F a y ■ N e b r a s k a - A l e x M a r t i n , C h a i r m a n . R e s e a r c h o n l e a f y s p u r g e c o n t r o l i n N e b r a s k a . A l e x M a r t i n . W y o m i n g R e s e a r c h R e p o r t s - H ■ P . A l l e y . C h a i r m a n . L e a f y s p u r g e , a p r o d u c t i o n t n i e f . S l i d e - t a p e S e r i e s . T o m W h i t s o n . S o i l r e s i d u e a n d l e a f y s p u r g e r o o t s t u d i e s . R o n V o r e . C O F F E E B R E A K E v a l u a t i o n o f g r o w t h r e g u l a t o r / h e r b i c i d e s . M a r k F e r r e l l . R e p e t i t i v e h f e r b i c i d e t r e a t m e n t s f o r l e a f y s p u r g e c o n t r o l . H . P . A l l e y . F o r a g e p r o d u c t i o n - l e a f y s p u r g e c o n t r o l c o m p a r i s o n s . T o m W h i t s o n . U S P A - U S F S ♦ M a p p i n g l e a f y s p u r g e c o m m i t t e e s f r o m a e r i a l p n o t o s . R i c h a r d M y h r e - U . S . F . S . , F t . C o l l i n s . E u r o p e a n r u s t f u n g i e v a l u a t e d f o r l e a f y s p u r g e c o n t r o l a t t h e P l a n t D i s e a s e L a b . W i l l i a m L . B r u c n a r d t - P l a n t D i s e a s e L a b , M a r y l a n d . D o e s 2 , 4 - D f o l l o w a s s i m i l a t e t r a n s l o c a t i o n i n l e a f y s p u r g e . S . E . L i n g l e a n d J . C . S u t t l e - U S D A M e t a b o l i s m a n d R a d i a t i o n R e s e a r c h L a b , F a r g o . P r e l i m i n a r y i n v e s t i g a t i o n s o n t h e e f f i c a c y o f c o m p o u n d s o f n a t u r a l o r i g i n a n d e x p e r i m e n t a l h e r b i c i d e s o n g r e e n ­ h o u s e g r o w n l e a f y s p u r g e p l a n t s . D a v i d C . D a v i s - U S i l X - A R S , F a r g o . C l i e m o t a x o n o m y o f l e a f y s p u r g e . K e n n e t h L . S t e v e n s - U S D A - A U S t B e r k e l e y . C h e m i s t r y a n d a l l e l o p a t h y o f l e a f y s p u r g e . C a r y D . M a n n e r s - U S D A - A R S , B e r k e l e y . Leafy Spurge Extension Program An extension program has been r e in i ­ t ia ted to increase public awareness and disseminate information on lea fy spurge. Herbicide demonstration p lo t s w il l be e s tab l ish ed a t 20 lo ca t ion s th i s year and tours and meetings w i l l be conducted throughout Montana. A one-to-one con su l ta ­ t ion serv ice w i l l a lso be o ffered to land owners to help so lv e th e ir spurge problem. A le a fy spurge monograph on the biology and control o f the p lant w i l l be published by December. SPURGE TOURS Leafy spurge tours w i l l be held around the s t a te in June and July . The tours should be informative and fun. A t e n ta t iv e schedule fo l low s . June 14 Roosevelt County (Snowden Bridge) June 15 Valley County (Hinsdale) June 28 Toole County (Shelby) July 6 Fergus County For more information about the tours contact your county ex tens ion agent.B a r b e c u e - F a i r g r o u n d s 8 : 3 0 p m B u s i n e s s M e e t i n g , C o u n t y C o u r t h o u s e B a s e m e n t . J u n e 2 2 , 1 9 8 3 THIRD ANNUAL WEED FAIR 7 : 3 0 a m - 4 : 3 0 p m F i e l d t o u r w i l l i n c l u d e : ( 1 ) C o m p a r i s o n s o f h e r b i c i d e t r e a t m e n t s o n l e a f y s p u r g e a p p l i e d f i v e y e a r s p r e v i o u s l y . ( 2 ) L e a f y s p u r g e r o o t s a m p l i n g t e c h n i q u e s . ( 3 ) A e r i a l a p p l i c a t i o n d e m o n s t r a t i o n . ( 4 ) G r o w t h r e g u l a t o r , h e r b i c i d e c o m b i n a t i o n s a n d n e w h e r b i c i d e i n t r o d u c t i o n s . R e g i s t r a t i o n c o s t s o f b e t w e e n $ 1 5 a n d $ 2 0 w i l l i n c l u d e a l l m e a l s w i t h t h e e x c e p t i o n o f b r e a k f a s t o n J u n e 2 1 s t . P r o g r e s s r e p o r t s a n d p r o c e e d i n g s w i l l b e p r o v i d e d f o r p a r t i c i p a n t s a t t h e m e e t i n g . F o r m o r e i n f o r m a t i o n p l e a s e c o n t a c e D r 1 H a r o l d A l l e y o r D r . T o m W h i t s o n P l a n t S c i e n c e D e p t . P . O . B o x 3 3 5 4 U n i v e r s i t y S t a . , L a r a m i e , W y o m i n g 8 2 0 7 1 . Fight Weeds and Win! The third annual weed f a i r w i l l be held in S t i l lw a te r County on July 23, 1983. The weed f a i r w il l include tours for farmers, ranchers, and small landowners; information booths; goat barbeque; crowning o f King Th is t le and Miss Morning Glory; o ld - t im e f id d l in g ; and a Weed Fair Dance. R eg ister before July 15 and pay only $5.00 per family . For more information contact S t i l lw a te r County Extension Service in Columbus, Montana (406)322-5334. Join us for a l o t o f fun and learn some valuable new methods o f plant manage­ ment! 119 Just c l i p out the fo l low ing r e g i s ­ tra t ion form and send i t to S t i l lw a te r County Extension Agency. Name _______________________________ Name of Spouse _____________________ Names/Ages of Children _____________ *I I Address _________________________________ 1 ------------------------ ZiP------------------------- Please check choice of lours, developed for: I _________Rancher Legislator/ I _________Farmer County Commissioner I _________Small l a n d o w n e r __________Spouse _________Pilot Flying F a rm e r __________ Children I VV ill you be joining us for the haibequc, cnter- I t.enment, ami dunce?______Yes_______No . Mail before Iuly 15 with check or money order for S5.00 to: I Stillvv.ilvr County Extension Ayenty Mikv th n is EDUCD n« I B n \ *J\)7 Sllhv.ttvl Li I Vtirr*-n Ag-S« V Coiun'hus. MT 5 ^ N M2 5.334 WEED BILL PASSES. BUT......... The 1983 Montana S ta te Legis la ture recen t ly passes a b i l l that provides approximately $87 ,000 .00 per year for weed research. However, the b i l l w i l l not be enacted unti l 1984. The old saying "better la t e than never" c e r ta in ly app lie s in th i s case! SHEEP ON SPURGE Research in i t i a t e d in the summer o f 1982 on weight gains o f lambs grazing on l e a fy spurge w i l l continue th i s summer. Sue Bartz , a graduate student in range sc ience a t Montana S ta te University i s recording lamb gains from pastures with 3 d i f f e r e n t treatments: I) l e a fy spurge con tro l led with chemicals; 2) l i g h t l e v e l s o f le a fy spurge in f e s ta t io n (10% plant composition) and; 3) heavy l e v e l s o f spurge in f e s ta t io n (20% or greater plant compos it ion ) . In add it ion , exclosures w il l be placed in each pasture to determine ewe and lamb use o f spurge. NORTH DAKOTA FUNDS FOR SPURGE Congressman Marlenee's o f f i c e indicated tha t part o f the program e f f o r t a t the USDA Research S ta t ion a t Sidney, MT w i l l be d irec ted toward noxious weed research. In add it ion , funding w i l l a lso be a va i lab le to Montana S ta te Un ivers ity for research on l e a fy spurge. LEAFY SPURGE SPREADS A 1982 survey o f l e a fy spurge in North Dakota has been completed and in d i ­ ca te s there are over 860,000 acres o f spurge in the s t a t e . This i s an increase o f over 150,000 acres compared to the 1981 est imate and because o f a very wet f a l l , l e a fy spurge growth should be vigorous th i s spring reported Dr. Rod Lym. The major areas o f increase are in the North Central and South Eastern parts o f the s t a t e , but nearly a l l 53 counties reported at l e a s t some increase in spurge acreage. In add it ion , the North Dakota Highway Department est imates over 87,000 m iles o f s t a t e and county roads have lea fy spurge growing along them. This i s up from 55,181 m iles reported in 1979. 120 WEED FUNDS VETOED The 1983 North Dakota S ta te L eg is la ­ ture introduced a b i l l to appropriate $500,000.00 for co s t share on le a fy spurge control in the s t a t e . The b i l l was passed by the Senate and House, but was vetoed by the Governor. This money, along with revenue ava i lab le to loca l weed boards, would have helped to fund a large program to stop the spread o f le a fy spurge in the s t a t e . WYOMING OBEREA UPDATE Oberea erythrocephala , a root-boring b e e t l e , was re leased in 1980 and 1981 in Fremont County and in 1982 in Lincoln County. The s ta tu s o f the r e le a s e program fo l low s . 1980 - (Release s i t e on Popo Agie Ranch) The s i t e was v i s i t e d on July I , 1982 but no adults were found. Only four p lants were located on the s i t e with po ss ib le Oberea s cars . One larva was d is se c ted from a stem in May, 1982. 1981 - (Release s i t e a t Lander) The s i t e was v i s i t e d on July 21 and Aug. 16, 1982. No adults were found on e i th e r occa ss ion . In Ju ly , 300 stems of l e a f y spurge were examined and 31 scars found. In August, o f 400 stems examined, 118 scars from Oberea were lo ca ted . 1982 - (Release s i t e a t A fton , 10 miles N.) On July 4 , 1982, 302 adu lts were re leased on le a fy spurge p lants dominating a h i l l s i d e (86 flowering s t em s /m ; . Male and female Oberea began copulating immediately. Some females, presumably mated in t r a n s i t , began chewing holes in stems as soon as they were re leased . BIOLOGICAL CONTROL CANADA Dr. Peter Harris, Agriculture Canada, reported that r e le a se s o f adult Aphthona f l ava and A. c yp ar is s ia s (spurge roo t­ feeding b e e t le s ) were made in Alberta , Saskatchewan, Ontario, Quebec and Manitoba. No breeding occurred in f i e l d cages in the former three provinces and the l a t t e r two remain to be checked. The b ee t le did breed on well-watered p lan ts in the labora­ tory and i t i s thought tha t they would fare b e t ter in the f i e l d with an early spring r e lea se s in ce the eggs require moist cond it ion s . Late f a l l r e le a se s o f larvae were made but cannot be checked un ti l the ground thaws. On cypress spurge in Ontario, Hyles euphorbiae, (spurge hawkmoth) in some placed reached d en s i t i e s o f up to 27 larvae /nr which led to complete d e fo l ia ­ t ion o f the weed in the spurge stand. In Saskatchewan, the root-boring bee t le Oberea erythrocephala continues to survive a t low d en s i t i e s . The problem r e la t e s to lack o f o v ip o s i t ion but the reasons for th i s are unclear. Currently host s p e c i f i c i t y t e s t s funded by Alberta are being concluded on the r o o t -b e e t le Aphthona cwalinae and have been s ta r ted on the ro o t -g a l l f l y Pegomya arqyrocephala. Saskatchewan i s funding a search for the d e fo l ia t in g moth Biston f id u c ia r i e s and the l e a f - t y in g moth Lobesia euphorbiana. At Regina, Sascatchawan, L_. euphorbiana i s being increased in the greenhouse for r e lea se in the spring o f 1983 as well as A. f lava and A. cypar is s ia s for further attempts a t estab lishment. A lso , screening i s underway on the d e f o l ia ­ t ing moth Minoa murinata and two aphids, Acyrthosiphum cypar is s ia e and Aphis e s u l a . * * * * I f anyone would l i k e extra copies o f th i s new s le t ter , to be added to the mailing l i s t , or more information on lea fy spurge, p lease contact: Celes t ine Lacey Plant & Soil Science Dept. Montana S ta te Univers ity Bozeman, MT 59717 121 w Leafy Spurge News PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN, MONTANA 5971 7 V o lum e IV A u g u s t 1983 I s s u e 3 % 1 : - ' % 'I 1 K -M ' n UP K K IT /., OK n WILL Cl T IlIK REST Ol U S !" WYOMING L e a f y S p u r g e S ym po s ium The s e c o n d d a y I n c l u d e d a b u s t o u r t h r o u g h t h e J e s s D r i s k l l l r a n c h w h e r e a n a c t i v e l e a f y s p u r g e c o n t r o l p r o g r a m h a s b e e n c o n d u c t e d . T h e c o n t r o l o b t a i n e d a n d t h e c o s t o f s u c h a p r o g r a m w a s d i s c u s s e d . T h e g r o u p a l s o v i e w e d t h e e x t e n s i v e r e s e a r c h p r o g r a m b e i n g c o n d u c t e d on l e a f y s p u r g e i n t h e a r e a , i n c l u d i n g t h e r e p e t i t i v e h e r b i c i d e p r o g r a m s t a r t e d i n 1 9 7 8 ; a h e l i c o p t e r T o r d o n 2K p e l l e t a p p l i c a t i o n d e m o n s t r a ­ t i o n a n d r o o t s a m p l i n g t e c h n i q u e s u s e d t o e v a l u a t e r o o t k i l l w e r e o b s e r v e d . An e x t e n s i v e h e r b i c i d e r e s e a r c h p l o t a r e a w as t o u r e d i n t h e a f t e r n o o n . T h e m o s t i n t e r e s t i n g r e s e a r c h p l o t s w e r e w h e r e t h e l e a f y s p u r g e h a d b e e n mowed a n d r e g r o w t h s p r a y e d w i t h low r a t e s o f B a n v e l 1 T o r d o n 22K a n d 2 , 4 - D LV e s t e r . T he t r e a t m e n t o f t h e 2 , 4 - D LV e s t e r w as e x c e l l e n t , i n d i c a t i n g a n e e d f o r m o r e r e s e a r c h i n t h i s a r e a . We a p p r e c i a t e a l l o f t h e h a r d w o r k a n d t im e t h a t e v e r y o n e i n Wyoming c o n t r i b u t e d t o make t h e s ym po s ium a s u c c e s s . C o n g r a t u l a t i o n s t o t h e U n i v e r s i t y o f Wyoming f o r h o s t i n g a n i n f o r m a t i v e a n d e n j o y a b l e L e a f y S p u r g e S y m p o s i u m ! T he f i r s t d a y o f t h e s ym po s ium w a s h i g h l i g h t e d w i t h r e s e a r c h r e p o r t s w h i c h g a v e a g o o d o v e r v i e w o f t h e c u r r e n t r e s e a r c h o n l e a f y s p u r g e . A s o c i a l h o u r a n d b a r b e c u e h o s t e d b y Dow, Ve I s i - c o l , U n i o n C a r b i d e , a n d J i r d o n C h e m i c a l C o m p a n i e s f o l l o w e d t h e r e p o r t s i n t h e e v e n i n g . M ov in g On D r . Tom W h i t s o n , who h a s b e e n v e r y a c t i v e i n t h e l e a f y s p u r g e r e s e a r c h p r o g r a m a c c e p t e d a p o s i t i o n a s E x t e n s i o n Weed S p e c i a l i s t a t O r e g o n S t a t e U n i v e r ­ s i t y . He r e p o r t e d J u l y I , 1 9 8 3 . We w i l l m i s s T o m ' s e x p e r t i s e a n d h a r d w o rk i n Wyom ing , b u t w i s h h im w e l l i n h i s n ew p o s i t i o n . M r . M a rk F e r r e l l , a P h .D . c a n d i d a t e i n Weed S c i e n c e , w i l l a s s u m e T o m ' s r e s p o n s i b i l i t i e s u n t i l t h e v a c a t e d p o s i t i o n i s f i l l e d . 122 M ore F u n d s f o r S p u r g e The Wyoming S t a t e D e p a r tm e n t o f A g r i c u l t u r e r e c e n t l y a w a r d e d t h e Weed S c i e n c e S e c t i o n a t t h e u n i v e r s i t y a $ 1 0 , 0 0 0 g r a n t t o a s s i s t i n l e a f y s p u r g e r e s e a r c h . MONTANA S p u r g e S a v e s L i v e s L e a f y s p u r g e i s c r e d i t e d w i t h s a v i n g l i v e s a t M o n t a n a ' s T h i r d A n n u a l Weed F a i r ! G o a t s t h a t w e r e d e s t i n e d t o b e t h e m a i n c o u r s e o f t h e b a r b e c u e f o r t h e f a i r w e r e s p a r e d t h e i r l i v e s when t h e y p r o v e d how e f f e c t i v e l y t h e y c o u l d c o n t r o l l e a f y s p u r g e a l o n g t h e Y e l l o w ­ s t o n e R i v e r . A l t h o u g h a f ew g o a t s c o n t r i b u t e d t o t h e d i n n e r , s e v e r a l p a i r s w e r e s p a r e d t o c o n t i n u e t h e i r s p u r g e c o n t r o l e f f o r t . T he Weed F a i r w a s a g r e a t s u c c e s s w i t h a b o u t 5 0 0 p e o p l e a t t e n d i n g t h e e v e n t . T h e f a i r s t a r t e d a t 1 2 : 3 0 p .m . J u l y 2 3 r d w i t h w eed t o u r s f o r e v e r y o n e i n c l u d i n g y o u t h , s p o u s e s , r a n c h e r s , f a r m e r s , w eed s u p e r v i s o r s a n d l e g i s l a ­ t o r s . H i g h l i g h t s o f t h e t o u r s i n c l u d e d c o n t r o l f o r f i e l d b i n d w e e d , C a n a d a t h i s t l e , w i l d o a t s , l e a f y s p u r g e a n d s p o t t e d k n a p w e e d ; r a n g e im p r o v e m e n t d e m o n s t r a t i o n p l o t s on s e e d i n g , m e c h a n ­ i c a l t r e a t m e n t s , a n d f e r t i l i z a t i o n ; s a g e b r u s h c o n t r o l w i t h m o w in g , h e r b i ­ c i d e s a n d c o n t r o l l e d b u r n i n g ; e s t a b l i s h ­ m e n t o f a g r a s s n u r s e r y ; a n d a h i s t o r i ­ c a l t o u r o f C o lu m b u s . K in g T h i s t l e , W i l b e r H o lm e s , a n d M i s s M o r n i n g G l o r y , M a ry P e t e r s o n , w e r e c r o w n e d i n a c e r em o n y f o l l o w i n g t h e b a r b e c u e . W i l b e r H o lm e s w a s o n e o f t h e r a n c h e r s who was i n s t r u m e n t a l i n u s i n g s h e e p f o r c o n t r o l l i n g l e a f y s p u r g e i n M o n t a n a , a n d M a ry P e t e r s o n h a s b e e n a "w e e d f i g h t e r " f o r many y e a r s . C o n g r a t ­ u l a t i o n s t o o u r w i n n e r s f o r t h e i r h e l p w i t h t h e WEED BATTLE. A s p e c i a l t h a n k s t o C h u c k E g a n , W ayne P e a r s o n , J o h n L a c e y , P e t e F a y , H e r b U h r i c h , a n d a l l o f t h e o t h e r p e o p l e who w o rk ed s o h a r d t o make t h e Weed F a i r a s u c c e s s . BLM P u r g e s S p u r g e The B u r e a u o f L a n d M a n a g em en t i n M o n t a n a i s u s i n g h e r b i c i d e s t o t r e a t a p p r o x i m a t e l y 995 a c r e s o f t h e i r l a n d t h a t i s i n f e s t e d w i t h l e a f y s p u r g e . T h i s i n c l u d e s l a n d i n t h e L e w i s t o w n , B i l l i n g s , M i l e s C i t y , P ow d e r R i v e r , a n d B i g D ry R e s o u r c e s A r e a s . T h e D i l l o n R e s o u r c e a r e a i s c o n ­ t r o l l i n g s p u r g e o n 2 4 0 a c r e s b y a l l o w i n g s h e e p g r a z i n g w i t h a n o - c o s t l i c e n s e . F o r m o re i n f o r m a t i o n a b o u t BLM1s w eed p r o g r a m s , c o n t a c t F r e d B a t s o n , M o n t a n a S t a t e O f f i c e 4 0 6 - 6 5 7 - 6 6 5 5 . S p u r g e T o u r s T h e 1983 L e a f y S p u r g e t o u r s h a d a r e c o r d t u r n o u t , w i t h o v e r 5 7 0 p e o p l e a t t e n d i n g t h e 9 t o u r s h e l d i n J u n e a n d J u l y . I t w a s g r e a t t o s e e s o many p e o p l e c o n c e r n e d a b o u t l e a f y s p u r g e c o n t r o l p r o g r a m s . T h e i r e n t h u s i a s t i c s u p p o r t o f e x t e n s i o n a n d r e s e a r c h e f f o r t s i s e s s e n t i a l t o d e v e l o p i n g a v i a b l e s p u r g e c o n t r o l p r o g r a m . T h a n k s t o a l l o f t h e c o u n t y a g e n t s , s o i l c o n s e r v a t i o n s e r v i c e p e r s o n n e l , s o i l c o n s e r v a t i o n d i s t r i c t s , a n d weed s u p e r v i s o r s who w o r k e d s o h a r d t o make t h e s e t o u r s a s u c c e s s . We a l s o a p p r e ­ c i a t e t h e h e l p a n d s u p p o r t f r om Dow C h e m i c a l Company who s p o n s o r e d t h e t o u r s . Two f a l l t o u r s a r e p l a n n e d f o r t h i s y e a r : S e p t . 6 P e t r o l e u m C o . C o n t a c t : C e l e s t i n e Lacey 9 9 4 - 4 6 0 1 S e p t . 8 C a r t e r Co . c o n t a c t : Pam C a s t l e b e r r y 7 7 8 - 2 8 9 1 123 NORTH DAKOTA C a r b o h y d r a t e s E f f e c t H e r b i c i d e Movem en t? I n 1 981 a n d 1982 l e a f y s p u r g e r o o t s a m p l e s w e r e t a k e n w e e k l y t o a 6 - i n c h d e p t h f r o m e a r l y A p r i l t o l a t e O c t o b e r . A n a l y s i s o f t h e s o l u b l e s u g a r s i n d i c a t e d s u c r o s e a s t h e m a j o r c a r b o h y d r a t e p r e s e n t w i t h a s l i g h t am o u n t o f g l u c o s e a n d f r u c t o s e a l s o p r e s e n t . T he s o l u b l e c a r b o h y d r a t e r e a c h e d maximum l e v e l s i n l a t e f a l l j u s t p r i o r t o f r e e z e - u p a n d c o n s t i t u t e d 16% o f t h e l e a f y s p u r g e r o o t m a t e r i a l o n a d r y w e i g h t b a s i s . C a r b o h y d r a t e l e v e l s f l u c t u a t e d g r e a t l y d u r i n g m id sum m er i n b o t h g r o w i n g s e a ­ s o n s . I t w a s f o u n d t h a t c a r b o h y d r a t e l e v e l s d e c r e a s e d a s t h e a v e r a g e w e e k l y t e m p e r a t u r e i n c r e a s e d ; c o n v e r s e l y , r o o t c a r b o h y d r a t e l e v e l s i n c r e a s e d a s t h e a v e r a g e w e e k l y t e m p e r a t u r e d e c r e a s e d . T h e s e f l u c t u a t i o n s i n c a r b o h y d r a t e m ov em en t c o u l d a f f e c t h e r b i c i d e t r a n s ­ l o c a t i o n a n d t h u s l e a f y s p u r g e c o n t r o l . R o o t s a m p l e s a r e b e i n g t a k e n t w i c e w e e k l y i n 1 983 s o t h a t a m o r e p r e c i s e p r e d i c t i o n o f p e r i o d s o f i n c r e a s e d c a r b o h y d r a t e a n d p e r h a p s h e r b i c i d e t r a n s l o c a t i o n t o t h e r o o t s y s t e m c a n be m a d e . D o l l a r s & S e n s e E c o n o m i c a l c o n t r o l o f l e a f y s p u r g e h a s b e e n a m a j o r g o a l o f t h e l e a f y s p u r g e p r o g r a m i n N o r t h D a k o t a . A n n u a l a p p l i c a t i o n o f T o r d o n p l u s 2 , A-D a t 0 . 2 5 p l u s 1 . 0 I b /A f o r 2 y e a r s h a s r e s u l t e d i n g r e a t e r f o r a g e p r o d u c t i o n a n d s i m i l a r l e a f y s p u r g e c o n t r o l c o m p a r e d t o T o r d o n a p p l i e d o n c e a t 2 . 0 I b / A a f t e r 3 y e a r s ( T a b l e I ) . B a n v e l a t 2 . 0 I b /A h a s g i v e n f a i r f o r a g e p r o d u c t i o n , b u t o n l y 39% l e a f y s p u r g e c o n t r o l . B a n v e l h a s g e n e r a l l y g i v e n b e t t e r l e a f y s p u r g e c o n t r o l i n w e s t e r n v e r s u s e a s t e r n N o r t h D a k o t a . A n n u a l a p p l i c a t i o n s o f 2 , A-D h a v e n o t r e s u l t e d i n l o n g - t e r m l e a f y s p u r g e c o n t r o l , b u t d o e s k i l l t h e t o p g r o w t h l o n g e n o u g h t o a l l o w i n c r e a s e d f o r a g e p r o d u c t i o n . T a b l e I . I.*.*afy s p u r g e c o n t r o l f r om v a r i o u s a n n u a l h e r b i c i d e t r e a t m e n t s o r a s i n g l e a p p l i a t l o n o f p i r l o r a m . T o t a l H e r b i c i d e R i t e f o r a g e p r o d u c t i o n N f t 1 ( I t ' /A ) ............( t ) ............ ( I b /A ) T i / * ! 14 50 4 , 0 9 0 23 P i c l o r a m + 2 , 4 - 0 • 0 . 2 5 * 1 . 0 20 68 4 ,0 8 6 IQ Dicamba 2 . 0 5 39 3,501 - 1 2 2 , 4 - 0 2 . 0 4 22 3 ,3 49 15 S i n g l e a p p l i c a t i o n (1930 ) P i c l o r a o 2 . 0 84 2 ,5 4 8 - 7 2 C o n t r o l 7 ,1 14 LSD ( 0 . 0 5 ) 24 16 4.N 8 ' E ' - ’- noa ic r e t u r n ir.-.i- 1 by " ' i n v e r t i n g f o r a g e p ro * > c t i c n t o h av a t J-’iS /T min is b u r r . I c i d e -.nl a p p l i c a t i o n c o s t . 2 , ^ - 0 a t $ ? . V / l b , • i i c a a b a a t $ 1 0 . 3 0 / 1 6 , p i r l o r a m a t $ ‘10 .0 0 / l b . A p p l i c a t i o n c o s t a t $ 2 . 0 5 /A . CANADA D r . P e t e r H a r r i s , A g r i c u l t u r e C a n a d a , r e p o r t e d t h a t t h e l a r v a e o f A p t h o n a f l a v a a n d A . c y p a r i s s i a s r e l e a s e d i n N ovem be r o f 1 982 w e r e r e c o v e r e d i n t h e s p r i n g o f 1 9 8 3 . T h i s i n d i c a t e s t h a t t h e l a r v a e a r e c a p a b l e o f o v e r w i n t e r i n g i n S a s k a t c h e w a n . * * * * * * * I f a n y o n e w o u l d l i k e e x t r a c o p i e s o f t h i s n e w s l e t t e r , t o b e a d d e d t o t h e m a i l i n g l i s t , o r m o r e i n f o r m a t i o n on l e a f y s p u r g e , p l e a s e c o n t a c t : C e l e s t i n e L a c e y P l a n t & S o i l S c i e n c e D e p t . M o n t a n a S t a t e U n i v e r s i t y B oz em an , MT 5 9 7 1 7 124 Leafy Spurge News PLANT & SOIL SCIkNCL DkPARTMbNT MONTANA STATE UNIVERSITY BOZEMAN, MONTANA 59717 Volume IV November I983 Issue 4 MAW . . . . MLclTLctfv Spu rge , I t neems no m a t t e r vh^ re you go - t h e r e NORTH DAKOTA Program Receives Boost D r . Calvin Messersm ith re p o r te d t h a t th e leafy s p u r g e con tro l p rog ram re ce iv ed a s ign if ic an t boost J u ly , 1983. P rogram enhancem en t fu n d s were p rov id ed by th e 1983 N . D . L eg is la tu re and in add i t io n , th e r e was r ed i rec t io n of some s c i e n t i s t s on s t a f f by th e Dir. of th e Ag . Exp . S ta . T he p rog ram enhancem en t ad d s a s ig n if ic an t biological con tro l and bas ic p la n t physio logy p rog ram and s tab i l iz e s th e chemical con tro l p rog ram . D r . C . M esse rsm ith , is th e overa l l leafy s p u r g e contro l p ro je c t c o o rd in a to r ; D r . D. Galitz , is in c h a rg e o f the p lan t phys io logy re s e a rc h ; D r . L. L it t le f ie ld , d i r e c t s th e d is ea se con tro l componen t; D r . R. Lym, c o o rd in a te s th e chemical con tro l p ro je c ts ; a nd D r . C a r lson , c ov e rs leafy sp u r g e con tro l with in s e c ts . R esea rch S u p p o r t s Recommendations The r e c en t recommendation of a d ­ d ing 2 ,9 -D with low Tordon r a t e s for leafy s p u r g e con tro l is be ing su p p o r te d by add it iona l e x p e r im en ts a c ro s s N .D . Figu re I : P e r c en t Leafy Spurge c o n t r o l w i th Tordon and 2 , 4 - 0 ap p l i e d s i n g u l a r l y and in comb ina t ion . Tordon 7 . 4 ^ 0 I b a . i . / A l b a . i . / A 0 . 0 1 . 0 1 . 5 2 . 0 0 . 0 0 . 0 30* 1 9* 30* 0 . 2 5 42 68 71 61 0 . 3 8 61 7/. 81 60 0 . 50 75 8 5 8 4 7 8 LSD o . o s ( f o r Tordon X 2 , 4 -0 ) »18 * 2 , 4 - 0 r a t e s a p p l i e d bo th s p r i n g and f a l l an n u a l ly Tordon a t 0 .25 Ib/A p lu s 2 ,4 -D a t 1.0 Ib/A applied annua l ly p rov ided enhanced con tro l o v e r e i t h e r h e rb ic id e a lone . T h is t r e a tm en t g r a d u a l ly r edu ce s a leafy s p u r g e s t an d while p rov id ing a n e t posi­ t iv e income of a b ou t $15.00 /A . 2 ,4 -D a t 1.0 to 2 .0 Ib/A app lied bo th s p r in g and fall r e s u l te d in 30% o r less leafy sp u r g e con tro l a f t e r 2 y e a r s . Leafy s p u r g e con tro l was no t e n h an c ed by inc rea s ing th e 2 ,4 -D r a te above 1.0 Ib/A e i th e r along o r with T o rd o n . In c reas ing th e To rdon ra te to 0 .38 o r 0 .5 Ib/A with 2 . 4 - D improved leafy s p u r g e contro l compared to To rdon a t 0 .25 Ib/A p lu s 2 . 4 - D, b u t the n e t economic r e t u r n from improved fo rage p ro duc t io n was n e a r 0 o r n eg a t iv e . Annual app lica t ions of T o r ­ don p lus 2 ,4 -D for 3 to 5 y e a r s will g ra d u a l ly r e d u c e a leafy sp u r g e s t a n d un ti l th e remaining iso la ted p a tche s can be spo t t r e a te d with h igh Tordon r a t e s . P a thogen s on S pu rg e D r. L a r ry L ittle fie ld r e p o r te d th a t s ev e ra l p a thogen s a r e be ing s tu d ied for th e i r e f fec t on leafy s p u r g e a t N .D .S .U . 125 Uromyces s t r i a t u s : S p u rg e p lan ts in - fec ted witR th e r u s t U. s t r i a t u s a re s e v e r e ly dw a r fe d . Ch lo ro t ic and exh ib i t d i s to r t io n s s u ch a s t h i c k e n ed , cu r led le av e s , s h o r te n e d in te rn o d e s and f la t­ ten ed s tem s . In fec ted p lan t s inva r iab ly die w ith in 3 to 4 weeks o f em ergence . U n fo r tu n a te ly , th e s t a g e of th e r u s t p r e s e n t in leafy s p u r g e is n o n r e p e a t in g , th u s in fec tion c anno t be s p r e a d from one s p u r g e p lan t to a n o th e r . Also, the al­ t e r n a t e h o s t which b e a r s th e rep ea t in g u red ia l s t a g e is a lfa lfa . C onsequen t ly t h e r e is li t t le chance th e r u s t can b e ­ come a b iocon tro l a g e n t fo r s p u r g e . U romyces d ic tyo spe rm a a n o th e r r u s t has been ob ta in ed from MT on a close re la tive o f leafy s p u r g e , E. d ic to y o sp e rm a . I ts e f f e c t iv e n e s s on Teafy s p u r g e will be t e s te d as soon as a su f f ic ien t supp ly of u r e d io sp o re s can be ob ta in ed . M ic ro sphae ra e u p ho rb ia e c au se s powdery mildew b u t does li t t le damage in th e f ie ld . Some eco ty p e s of s p u r g e a r e more s e v e r e ly a f fec ted th an o t h e r s . Th is p a thogen m ight p rov e u se fu l in c h a r a c ­ te r iz in g d i f f e r e n t e co typ e s o f s p u r g e . A l te rn a r ia tenu iss ima f . s p . e upho rb ia e is FRe most p rom is ing p a thogen for s p u r g e b iocontro l iden t if ied to d a te . S tu d ie s by D r . Joe K ru p in s k y , have shown t h a t th i s p a thogen c au se s s e v e re leaf s p o t t i n g , c a n k e r s th a t g i r d le th e s tem , d ie -b a ck o f aeria l p o r t io n s , f r u i t d e c a y , and reduc t io n in seed s e t . The A l te rn a r ia p a thogen is w id esp read bu t seems to do g r e a t e s t damage in p ro te c ted a r e a s s u ch as th e s h e l t e r b e l t s , within clumps o f bu ffa lo b e r r y b u sh e s and u n d e r t r e e s a long s t r e am s . G reenhouse t e s t s o f v i r u le n c e of many d i f f e r e n t A l te rn a r ia iso la tes will b eg in in mid Oct. 1983. Limited field t e s t s o f th e v i r u len t iso la tes will be made in N .D . and MT. d u r i n g summer o f 1984. S tu d ie s on Sclerotimum ro l f s i i , a soil b o rn e p a th o g e n , a r e be ing e x p and ed . The po ten t ia l p rob lems a ssoc ia ted with th e wide ho s t r a n g e of th e pa thogen m ight p r e s e n t major b a r r i e r s to its use in biological con tro l p rog ram s . COLORADO Mapping Leafy S p u rg e Dick M yh re , USDA-FS a t F t . Coll ins , CO r e p o r te d t h a t a r e s e a rc h s t u d y looking a t th e in v en to ry a nd an a ly s is of leafy s p u r g e s i te s has been in p ro g r e s s a t th e U .S .F . S . Rocky M tn . F o re s t and Range Exp . S ta . The s t u d y u ti l izes g ro u n d da ta and remote s en s ing te c h n iq u e s to: I) Develop a q u an t i ta t iv e app ro a ch to leafy s p u r g e community d e ­ s c r ip t io n ; 2) Determ ine the feas ib il i ty of mapping a r e a s fo r leafy s p u r g e in f e s t ­ a t io n s ; and 3) D eterm ine se lec t so i l-s i te r e la t io n sh ip s o f leafy s p u r g e . Mr. Myhre is work ing on th e te chn iqu e s for u s ing aer ia l p h o to g r a p h y to locate and map leafy sp u r g e in f e s ta ion s . The t e s t is compar ing photo sca le s , film t y p e s , and s e a so n s (p eak flowering an d fall co lora tion) to de te rm ine the comb ina t ion (s ) b e s t s u i te d for la rge a rea s u r v e y s . The ae r ia l p h o to g r aphy and g ro u n d da ta u sed in th e s tu d y were a cqu i r e d in th e Devils T ow e r , WY a re a . Resu l ts of th i s s t u d y will be u sed to recommend s c a le / f i lm /s e a son combina­ t ions for in v e n to r i e s , a c cu ra cy and cost t r a d eo f f s be tween medium and small scale pho to s u r v e y s , and th e amount of a c c u r ­ acy th a t can be ob ta in ed for a c re ag e e s t im a te s . The an t i c ip a ted final p ro d u c t shou ld be a u s e r s g u id e / handbook cove r ing aerial pho to spec if ic a t ion s , photo in t e rp re ta t io n te c h n iq u e s , t r a in ing a id s , e tc . Fall T o u r s Approx imate ly 155 people a t t e n d e d leafy sp u r g e to u r s held in C a r te r and Petro leum Coun ties d u r i n g S ep tem be r . A specia l ta n k s to E v e r e t t B rady , Dave Ph il l ip s , D a r ry ld K au tzm an , Pam Cas te l - b e r r y , Norman Campbell and o th e r s who worked h a rd to make th e to u r s a s u c c e s s . We also a pp re c ia te th e he lp and su p p o r t of Dow Chemical C o . , who spon so red th e t o u r s . 126 Pulling T og e th e r B ruce Maxwell r e p o r te d th a t e x p e r i ­ ments h ave been conduc te d to d e te rm in e if pu ll ing leafy s p u r g e could con tro l r e ­ g row th . Plots were hand pulled e v e ry two weeks th r o u g h o u t th e 1982 g row ing s e a son . Reg row th was m easu red on Jun e 12, 1983 an d S ep t . I, 1983. The Ju n e ra t in g showed no s ign if i ­ c a n t d e c re a s e in leafy s p u r g e s tems p e r s q u a r e foot on any of th e pu ll ing d a te s , b u t v isua l r a t i n g s ind ica ted up to 701 con tro l due to th e s t u n te d n a tu r e of the r e g r ow th . Visual r a t i n g s taken on S ep t . I, 1983 showed a maximum of 25% contro l o v e r all th e pu ll ing d a t e s . T h is ind i­ c a te s th a t th e b e s t time to pull leafy s p u r g e for maximum con tro l of reg row th is mid to late J u n e . D u r ing th e 1983 g row ing season mach ines were u sed to pull leafy s p u r g e . Machine pull ing was compared with mowing, 2 ,4 -D app l ic a t io n s , To rdon ap p l i ­ ca t io n , and 2 , 4 - 0 t r e a tm en ts following pu ll ing and mowing. P re l im inary r e s u l t s from th i s fall ind ica ted th a t a s ing le s p r in g app lica t ion o f 2 ,4 -D amine a t 2 Ibs /A and machine pu ll ing with a follow­ up t r e a tm en t o f 2 ,4 -D r e g row th a f t e r pu ll ing p rov id ed th e b e s t con tro l of leafy s p u r g e . The 2 ,4 -D t r e a tm en t alone p ro ­ v id ed th e g r e a t e s t amount of perenn ia l g r a s s p ro d u c t io n , however g r a s s w e igh ts were only s ign if ic an t ly g r e a t e r than the mowing t r e a tm en ts . The u n t r e a t e d check p ro du c ed the most p e renn ia l g r a s s on a biomass b a s i s . CANADA New Insec ts? D r . P e te r H a r r i s has subm it ted a p roposa l to s c r e en s ix new in s e c ts for th e biological con tro l of leafy s p u r g e and C y p r e s s s p u r g e in C anada . T he in sec ts a r e : Ap thona czw a l in ae , la rvae feed on roo ts 6? s p u r g e ; A cy r tho s iphon c y p a r i s s i a e , an aph id ; Minoa m u r in a t a , a moth , la rv ae feed on flowers and leaves; Aphis e u p h o rb i a e , an aph id ; Pegoma a q ry r o c e p h a l a , la rv ae mine th ro u g h sh o o t s , ga lls a r e formed a t the base of th e shoo t ; Lobesia o c c id e n t i s , a stem b o r e r . WYOMING Shoo t/Roo t Contro l S tudy *18 Mark Ferre l l r e p o r te d th a t p as t s t u d ie s a t temp t ing to co r r e la te th e s h o o t / ro o t ra t io of v a r io u s he rb ic id e t r e a tm en ts on leafy s p u r g e have not been as su cces s fu l as d e s i r e d . In 1983, co re samples from th e 0-18 inch soil d ep th were e x t r a c te d from s e ­ lec ted he rb ic id e p lo ts e s tab l i sh ed in 1978. The p lo ts which were se lec ted for samp­ ling ranged from 78 to 100% leafy sp u r g e shoo t con tro l ( ev a lu a ted 1982). O rig inal t r e a tm en ts of T o rdon and Banvel were r e t r e a t e d with T o rd o n , 2 ,4 -D amine, B anv e l , and a combination of B an v e l / - 2 ,4 -D amine in 1979, 1980, 1981, 1982, and 1983. The To rdon t r e a tm en ts were te rm i­ n a ted with th e 1981 app lica t ion . Total v eg e ta t iv e root biomass was s c r e en ed from the r e s p e c t iv e core samples , t r a n sp la n t e d into g r e e n h o u s e soil and moved to th e g r e e n h o u s e for r e g e n e r ­ ation eva lu a t ion s . The root r e g en e r a t io n s t u d y showed leafy s p u r g e r eg row th from the o r ig in a l / - r e t r e a tm en t combinations of: Banvel 4L /2 ,4 -D amine a t 4+2 Ib a i /A , Banvel 4L /To rdon 22 K a t 4+0.5 Ib a i /A , Tordon 22K /Tordon 22K a t 0 .5+ 0.5 Ib a i /A , To rdon 22K/ Banvel 4L+ 2 ,4-DA a t 1+1+2 Ib a i/A and To rdon 22K/ Banvel 4L+2,4-DA a t 2+1+2 Ib a i /A . No o r i g in a l / r c t r e a tm en t p lo ts main­ ta in ing 100% shoo t con tro l in 1982 showed any leafy s p u r g e re g row th from th e 0 to 18 inch d e p th . T h e se t r e a tm en ts were To rdon 22K /Tordon 22K a t 0.5+1 Ib a i /A , To rdon 22K /Tordon 22K a t l+l Ib a i /A , To rdon 22K /Tordon 22K a t 2+1 Ib a i /A , To rdon 22K/Banvel 4L a t 2+2 Ib a i /A , Banvcl 4L /To rdon 22K a t 4+1 Ib a i /A , and C h eck /T o rdon 22K a t 0+1 Ib a i /A . A lthough the shoo t o r root biomass was no t m easu red it a p p e a r s th a t the r eg en e ra t io n s tu d y in i t ia ted in 1983 may be a method of d e te rm in ing the re cove ry ab i l i ty of leafy s p u r g e u n d e r v a r io u s o r ig in a l / r e p e t i t iv e h e rb ic id e t r e a tm en ts . ********** For more information o r to be added to th e mailing l i s t , c o n ta c t : Celes t ine Lacey Plan t 6 Soil Sc ience Dept. Montana S ta te U n ive rs i ty Bozmean, MT 59717-0002 127 Leafy Spurge News PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN, MONTANA 59717 VOLUME V FEBRUARY 1984 ISSUE I UHOOEE . . . THOSE UMBS OF 0U8S SURE CREU B lC AHU TOUCH ON THIS LUFY SPURCE PASTURE I MONTANA NEWS Lambs G a in on L e a f y S pu rg e Sue B a r t z r e p o r t e d t h a t d u r i n g t h e summer o f 1982 and 1983 , f i e l d r e s e a r c h was c o n d u c t e d t o d e t e rm i n e t h e n u t r i t i o n a l v a l u e o f l e a f y s p u r g e a s a f o r a g e compo­ n e n t f o r ew es and l am b s . D a ta c o l l e c t e d d u r i n g t h e s e two p e r i o d s a r e c u r r e n t l y b e i n g a n a l y z e d and some i n t e r e s t i n g p r e l i m i n a r y o b s e r v a t i o n s h a v e b e e n n o t e d : * Lambs g r a z i n g l e a f y s p u r g e i n f e s t ­ ed p a s t u r e s showed a s i g n i f i c a n t l y h i g h e r w e i g h t g a i n t h a n t h o s e lambs g r a z i n g o n l y n a t i v e g r a s s e s d u r i n g t h e s i x -w e e k d a t a c o l l e c t i o n p e r i o d . Weigh t g a i n s o f l am b s g r a z i n g s p u r g e a v e r a g e d 5 p o u n d s h e a v i e r t h a n w e i g h t g a i n s o f l am bs g r a z i n g o n l y g r a s s . * B r e e d i n g r e c o r d s o f t h o s e ewes h a v i n g e a t e n l e a f y s p u r g e ( t h e summer- p r i o r t o b r e e d i n g ) showed a b s o l u t e l y no r e b r e e d i n g p r o b l em s o r l am b in g d i f f i ­ c u l t i e s due t o t h e i n g e s t i o n o f l e a f y s p u r g e . * U t i l i z a t i o n d a t a a r e s t i l l b e i n g a n a l y z e d t o d e t e r m i n e t h e p e r c e n t " d i s a p p e a r a n c e " o f g r a s s and s p u r g e a s a r e s u l t o f s e l e c t i v e g r a z i n g by s h e e p . P r e l im i n a r y r e s u l t s a r e show ing t h a t s h e e p a t e a s i g n i f i c a n t amount o f t h e s p u r g e t h a t was a v a i l a b l e t o t h em , t h e r e b y s u p p o r t ­ i n g p r e v i o u s r e s e a r c h w h ic h showed t h a t a f t e r a 2 t o 3 w eek a d j u s tm e n t p e r i o d , s h e e p w ou ld s e l e c t i v e l y consume 40 t o 50% o f t h e i r d i e t a s l e a f y s p u r g e . Do Doves S p r e a d Spu rg e ? B ruce M axwell r e p o r t e d t h a t a c o ­ o p e r a t i v e s t u d y b e tw e e n Montana S t a t e U n i v . a nd D av id B l o c k s t e i n o f t h e B e l l Museum o f N a t u r a l H i s t o r y , U. o f M i n n . , h a s b e e n u n d e r t a k e n t o d e t e r m i n e i f l e a f y s p u r g e s e e d i s d i s p e r s e d by m o u rn in g d o v e s . P r e l im i n a r y r e s u l t s i n d i c a t e t h a t a l l l e a f y s p u r g e s e e d s t h a t h a v e p a s s e d t h r o u g h t h e d o v e s ' i n t e s t i n e s a r e n o t v i a b l e . S eed m a t e r i a l was a l s o c o l l e c t e d f rom t h e g i z z a r d an d c r o p o f s e v e n d o v e s . No v i a b l e l e a f y s p u r g e s e e d s w e r e fo u n d i n t h e g i z z a r d s a n d o n l y one v i a b l e s e e d was fo und i n t h e c r o p . 128 T h e se d a t a i n d i c a t e t h a t m o u rn in g d ov e s may n o t b e im p o r t a n t i n t h e d i s p e r s a l o f l e a f y s p u r g e s e e d s . B l o c o n t r o l U pda te D r . Bob N o w i e r s k i & J im S t o r y r e p o r t e d t h a t t h e s p u r g e hawk moth H y le s e u p h o r b i a s was c o l l e c t e d on a h i l l s i d e n o r t h o f Bozeman d u r i n g 1982 & 1983. T h e se i n s e c t s a r e p r o p a g a t e d d u r i n g t h e w i n t e r f o r r e d i s t r i b u t i o n t o o t h e r a r e a s . I n 1983 , a p p r o x im a t e l y 350 l a r v a e , p u p ae & a d u l t s w e r e r e l e a s e d a t two s i t e s i n G a l l a t i n and T e to n C o u n t i e s . F e e d i n g t e s t s a r e b e i n g c o n d u c t e d t h i s w i n t e r t o i d e n t i f y t h e t y p e s o f l e a f y s p u r g e p r e f e r r e d by t h e s p u r g e hawk m o th . P l a n t t y p e s t h a t a r e p r e f e r r e d by H y le s a nd o f f e r s u r v i v o r s h i p o f t h e mo th w i l l be t a r g e t e d f o r r e l e a s e s t h i s s p r i n g . NORTH DAKOTA NEWS *28 L e a fy S p u rg e Symposium Mark y o u r c a l e n d a r f o r t h e 1984 L e a fy S pu rg e Symposium t o b e h e l d on J u n e 27 and 28 a t D i c k i n s o n , ND. T h i s y e a r ' s p r o g ram w i l l h i g h l i g h t b i o l o g i c a l c o n t r o l w i t h an u p d a t i n g on c u r r e n t r e s e a r c h and a c t u a l c o n t r o l e f f o r t s . P a r t o f t h e p r o g ram w i l l c o v e r r e s e a r c h on taxonomy o f t h e l e a f y s p u r g e com p lex and i t s im p o r t a n c e i n d e ­ v e l o p m e n t o f c o n t r o l p r o g r a m s . C h em ic a l c o n t r o l w o rk w i l l b e c o v e r e d i n s h o r t u p ­ d a t i n g r e p o r t s . A h a l f - d a y t o u r i s a l s o p l a n n e d . D i c k i n s o n i s c l o s e t o Medora and R o o s e v e l t P a r k s , so p l a n on b r i n g i n g y o u r f a m i l y a n d sp e n d some t im e i n t h i s b e a u t i ­ f u l a r e a o f N o r t h D ak o ta b e f o r e o r a f t e r t h e m e e t i n g . I f you p l a n t o f l y commer­ c i a l a i r l i n e s , a r r a n g e t o f l y t o B ism a rc k and p r o v i d e D r . R u s s e l l L o re n z w i t h y o u r a r r i v a l t im e s o s h u t t l e s e r v i c e t o D i c k i n s o n c a n be a r r a n g e d . D i c k i n s o n d o e s h a v e an e x c e l l e n t a i r s t r i p f o r p r i v a t e a i r c r a f t . P r e - r e g i s t r a t i o n i n f o r m a t i o n w i l l b e p r o v i d e d a u t o m a t i c a l l y t o GPC-14 c om m i t t e e members and t h o s e who h a v e a t t e n d e d r e g u l a r ­ l y . O t h e r s who w i s h t o h ave t h e i r names on t h e m a i l i n g l i s t o r f o r a d d i t i o n a l i n f o rm a ­ t i o n c o n c e r n i n g t h e m e e t i n g p l e a s e c o n t a c t D r . R u s s e l l J . L o r e n z a t 7 0 1 - 6 6 3 -6 4 4 5 o r w r i t e t o h im a t Box 4 5 9 , Mandan , ND 58554 . SEE YOU IN JUNE1. L e a fy S p u rg e N u r s e r y Dr . Rod Lym r e p o r t e d t h a t t h e l e a f y s p u r g e n u r s e r y , s t a r t e d by D r . M e lv in M cCar ty i n 1978 , h a s b e e n removed f rom L i n c o l n , NE and w i l l now be m a i n t a i n e d a t Bozeman, MT and F a r g o , ND. B e fo r e h i s r e t i r e m e n t . D r . M cCar ty c o l l e c t e d 39 l e a f y s p u r g e s p e c im e n s f rom 16 s t a t e s , 2 C a n a d i a n p r o v i n c e s and A u s t r i a . T h i s c o l l e c t i o n w i l l b e a d d ed t o t h e c u r r e n t n u r s e r y a t NDSU w h ic h c o n s i s t s o f s p e c im e n s f rom s e v e r a l a r e a s o f ND and MN. Any d i f f e r e n c e s i n t h e s p e c im e n ' s g r ow th p a t t e r n s o r b i o l o g i c a l c o m p o s i t i o n m u s t b e i d e n t i f i e d b e f o r e b i o l o g i c a l c o n t r o l c a n become a r e a l i t y . E c o n om ic a l S p u rg e C o n t r o l Dr . Ron Lym r e p o r t e d t h a t a n n u a l a p p l i c a t i o n s o f T o rd o n o r T o rdon p l u s 2 ,4 -D f o r 3 y e a r s h av e g r a d u a l l y r e d u c e d l e a f y s p u r g e s t a n d s and a r e much more e c o n o m ic a l t h a n s i n g l e T o rdon t r e a t m e n t s a t h i g h r a t e s . T o rdon a t 0 . 5 I b /A p r o v i d e d 75% l e a f y s p u r g e c o n t r o l a f t e r t h r e e a n n u a l t r e a t m e n t s . T o rdon a t 0 . 2 5 I b /A a v e r a g e d o n l y 42% c o n t r o l a f t e r t h r e e a p p l i c a t i o n s , b u t when t a n k m ixed w i t h 2 ,4 -D a t 1 . 0 and 2 . 0 I b /A c o n t r o l a v e r a g e d 71%. The c o s t o f t h e a n n u a l t r e a t m e n t s i s $15 t o $ 2 0 / y e a r o r a t o t a l o f $45 t o $60 a f t e r 3 y e a r s c om pa red t o T o rdon a t 2 . 0 I b /A w h ic h c o s t s $80 t o $90 /A and m us t b e r e a p p l i e d e v e r y 3 y e a r s t o m a i n t a i n s a t i s f a c t o r y c o n t r o l i n ND. No T o rdon r e s i d u e was f o u n d i n t h e s o i l a f t e r t h r e e a n n u a l a p p l i c a t i o n s t h u s t h e g e n e r a l i n c r e a s e i n l e a f y s p u r g e c o n t r o l was d ue t o a g r a d u a l s t a n d r e d u c t i o n and n o t t o an i n c r e a s e d T o rdon l e v e l t h a t wou ld p r e v e n t r e e s t a b l i s h m e n t . 129 P a th o g e n U pda te D r . L a r r y L i t t l e f i e l d r e p o r t e d t h a t em p h a s i s d u r i n g t h e p a s t 4 m on th s h a s b e e n on A l t e r n a r i a t e n u i s s im a e u p h o r b i a e a s a p o s s i b l e p a t h o g e n f o r b i o c o n t r o l . I s o ­ l a t e s o b t a i n e d f rom W i s c o n s i n , M in n e s o t a , M on ta n a , N o r t h D a k o t a , a nd S o u th D ako ta h a v e b e e n t e s t e d . So f a r o n l y o ne i s o l a t e f rom N o r t h D ak o ta h a s c a u s e d s e r i o u s dam­ ag e t o i n o c u l a t e d p l a n t s . T h a t i s o l a t e (S S - 4 ) was o b t a i n e d f rom J . M. K r u p in s k y (Mandan , ND) and was t h e o ne u s e d i n h i s e a r l i e r s t u d i e s . T h re e d i f f e r e n t s p u r g e e c o t y p e s h a v e b e e n t e s t e d ; two a r e s e v e r e ­ l y damaged by S S -4 , b u t one i s n o t . How­ e v e r , f o l l o w i n g d e a t h o f t h e s p u r g e l e a v e s and s t e m s , h e a l t h y l a t e r a l b r a n c h e s u s u a l l y a r i s e f rom t h e s t em b e low t h e d e ad a r e a . F i e l d t e s t s o f t h e SS-4 A l t e r n a r i a a r e p l a n n e d f o r summer 1984 i n Mon tana and N o r t h D a k o t a . S c l e r o t l u m r o l f s i i , o b t a i n e d f rom D. E. M a t h r e , Mon tana S t a t e U n i v . , w i l l k i l l a l l a b o v e g ro u n d p o r t i o n s o f s p u r g e p l a n t s g r ow in g i n v e r m i c u l i t e . However , h e a l t h y y oung s h o o t s b e g i n t o em e rg e , a nd w i t h i n 60 d a y s a f t e r i n o c u l a t i o n t h e p o t i s a g a i n f u l l o f v i g o r o u s s p u r g e p l a n t s . S c l e r o t l n l a s c l e r o t i o u r u m , t h e n o r t h ­ e r n c o u n t e r p a r t t o S c l e r o t l u m r o l f s i i , h a s n o t shown any p a t h o g e n i c i t y on s p u r g e . E x p e r im e n t s t e s t i n g d i f f e r e n t m e th o d s o f i n o c u l a t i o n a r e s t i l l u n d e rw ay w i t h t h i s f u n g u s . WYOMING NEWS Mowing S e t s Up H e r b i c i d e T r e a tm e n t ! *I D r . H a r o l d A l l e y r e p o r t e d t h a t p l o t s w e r e e s t a b l i s h e d n e a r H u l e t t , WY t o d e t e r ­ m ine t h e e f f e c t i v e n e s s o f mowing , p r i o r t o t r e a tm e n t w i t h h e r b i c i d e s , on c o n t r o l l i n g l e a f y s p u r g e s h o o t r e g r o w t h . L e a f y s p u r g e p l a n t s w e r e mowed w i t h i n I t o 2 i n c h e s o f g r o u n d l e v e l on Ju n e 3 0 , 1982 , 21 d a y s p r i o r t o t r e a tm e n t w i t h h e r b i ­ c i d e s . T r e a tm e n t s i n c l u d e d a p p l i c a t i o n s o f l i q u i d f o r m u l a t i o n s o f B anv e l a t 1 . 0 I b /A , T o rdon a t 0 . 5 I b /A , a n d 2 ,4 -D LVE a t 1 . 0 I b /A . Shoo t c o u n t s made May 19 , 1983 (one y e a r a f t e r t r e a t m e n t ) i n d i c a t e d t h a t mowing p r i o r t o h e r b i c i d e t r e a tm e n t may h a v e p o t e n ­ t i a l f o r r e d u c e d r a t e s o f c h e m i c a l f o r l e a f y s p u r g e s h o o t c o n t r o l . The t r e a tm e n t o f 1 . 0 I b /A o f 2 ,4 -D LVE was a s e f f e c t i v e a s 0 . 5 I b /A o f T o rdon r e s u l t i n g i n 19 and 86% s h o o t c o n t r o l , r e s p e c t i v e l y . However , more d a t a a r e n e c e s s a r y t o f u l l y e v a l u a t e t h e v a l u e o f mowing a s e t u p t r e a t m e n t f o r c o n t r o l l i n g l e a f y s p u r g e . A d d i t i o n a l e x p e r im e n t s a r e p l a n n e d f o r t h e summer o f 1984. 2 ,4 -D LVE T r e a tm e n t s P r i o r t o T o r d o n ! 17 Dr . A l l e y r e p o r t e d t h a t an e x p e r im e n t was e s t a b l i s h e d J u n e 16 , 1982 , 5 m i l e s s o u t h o f H u l e t t , WY, t o e v a l u a t e t h e u s e o f 2 , 4 -D LVE a s a s e t u p t r e a t m e n t p r i o r t o a p p l i c a ­ t i o n o f l i g h t r a t e s o f To rdon on l e a f y s p u r g e . S e tu p t r e a t m e n t s w i t h 2 ,4 -D LVE w e r e made I day and 17 d a y s p r i o r t o a p p l i c a t i o n o f l i q u i d f o r m u l a t i o n s o f 0 . 5 and 1 . 0 I b /A o f T o rd o n . S hoo t c o u n t s made May 18, 1983 (one y e a r a f t e r t r e a t m e n t ) showed a l l T o r d o n / 2 , 4 -D LVE s e t u p c o m b i n a t i o n s g a v e 100% s h o o t c o n t r o l . T h e re was no d i f f e r e n c e i n l e a f y s p u r g e s h o o t c o n t r o l b e tw e e n t h e I d a y and 17 d ay s e t u p t r e a t m e n t s w i t h 2 ,4 -D LVE. T hese r e s u l t s w o u ld i n d i c a t e t h a t 2 , 4 -D LVE a s a s e t u p t r e a t m e n t , f o l l o w e d by low r a t e s o f T o rd o n , may b e an e f f e c t i v e m eans o f c o n t r o l l i n g l e a f y s p u r g e s h o o t g r o w th . F u r t h e r e x p e r im e n t s a r e p l a n n e d f o r t h e summer o f 1984 . * F o r a d d i t i o n a l i n f o r m a t i o n o r t o b e a d d e d t o t h e m a i l i n g l i s t , p l e a s e c o n t a c t : C e l e s t i n e L ac ey P l a n t & S o i l S c ! . D e p t . Montana S t a t e U n i v e r s i t y Bozeman, MT 59717 130 Leafy Spurge News PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN. MONTANA 59717 VOLUME V APRIL 1984 ISSUE 2 LEAFY SPURGE SYMPOSIUM Dickenson , N.D. June 2 7 -28 , 1984 T en t a t i v e June 26 6 :00 p.m. June 27 6 : 3 0 - 7 : 3 0 a .m. 8 : 0 0 - 8 : 1 5 a.m. Tour o f Lea fy Spu rge P l o t s Ramada Inn Group b r e a k f a s t Welcome & I n t r o d u c t i o n - Or. R u s s e l l Lorenz 8 : 15 -12 : 00 8 : 1 5 - 9 : 0 0 a .m. Lea fy Spu rge Taxonomy - Dr. A l Ina S t a h ev i ch ( M o d e r a t o r ) C y to g e n e t i c s - Dr. A l ina S t a h e v i t c h , O t tawa , O n t a r io - Dr. S c h a e f f e r , Montana 9 :00 -1 0 : 3 0 a .m. Chemotaxonomy - Or . John Evans , Utah - Dr. Paul Mah lberg , I nd i an a - Dr. Dave D av is , ARS, Fargo - Dr. Don G a l i t z . North Dakota 10:30 a .m. 10 :45 -1 2 :00 12 :00 -1 :00 p.m. 1 :0 0 -3 :1 5 p.m. Break D i s cu s s i o n Groups - Taxonomy Noon l unch - Group B io l o g i c a l Con tr o l o f Le a fy Spurge - Dr. Robert N ow ie r sk i , Moderator Montana - N ow ie r s k i , Rees Wyoming - Levine North Dakota - C a r l s o n , L i t t l e f i e l d Canada - H a r r i s Idaho Washington Oregon We apologize fo r an e r r o r made in th e Feb . 1984 is sue o f th e Leafy S p u rg e News. T he e r r o r was made in th e Wyoming sec t ion u n d e r Mowing S e ts Up Herb ic ide T r e a tm en ts . The p e r c e n t shoot con tro l w ith 1 .0 Ib/A of 2 , 4 - 0 LVE should be 91% r a t h e r th an 19%. Please make th is c o r r e c t io n in y ou r F e b ru a r y new s le t te r ! LEAFY SPURGE SYMPOSIUM Mark you c a lenda r fo r th e b igg es t s p u r g e e v e n t in 1984! The Leafy Spu rg e Symposium will be held on Ju n e 27 and 28 a t D icken son , N .D . S p eak e rs will inc lude r e s e a r c h e r s from C an ad a , M on tana , U tah , In d iana , North D ako ta , Sou th Dakota , Idaho , Wash ing ton , O regon , N eb ra sk a , and M inneso ta . A de ta i led ag enda of th e symposium follows. 3 :1 5 - 3 : 3 0 p.m. 3 : 3 0 -4 : 4 5 p.m. 4 :4 5 p.m. 5 :30 p.m. 6 :3 0 p.m. Break D i s cu s s i o n Groups - B io l o g i c a l Cont ro l Announcements No h o s t s o c i a l Banquet (Group Meal) - spea ker D r . R o b e r t N o w l e r s k i June 28 6 : 3 0 - 7 : 4 5 a .m. 7 :00 a .m . 8 :0 0 - 9 : 0 0 a .m. 9 : 0 0 -11 : 30 a.m. Group b r e a k f a s t Bus in e s s Mee t ing ( b r e a k f a s t program) R epo rt s f rom D i s cu s s i o n groups Chemical and C u l t u r a l Con tr o l - update** Dr. C a l v i n M es s e r sm i t h , Moderator Montana - Dr . P e t e r Fay, e t . a l . Wyoming - Dr. Ha ro ld A l l ey North Dakota - Dr. Rod Lym, Or. Cal Mes se rsm it h Nebraska 131 10:00 a .m . Break South Dakota Utah Minneso ta - Or. Dav id B le sboe r 11: 30 a .m . Check o u t o f Motel 11: 45-12 :45 1 :00 -6 :00 p.m. 6 :00 p.m. Noon Lunch - group meal Bus t o u r t o spu rg e problems and r e s e a r c h p l o t s West o f D ick in son and in t h e bad lands Evening meal a t Medora Othe r s p ea k e r s t h a t may a t t e n d : - B i l l B r u c k a r d t . F r e d e r i c k . MO - P a tho logy - Ken S te v en s , ARS-USOA. B e rk e ly Lab- Chem is try - Gary Manners. ARS-USOA. B e rk e ly Lab - Chem is try - Duane Ebke1 Nebraska • • May be l im i t e d t o one s p e a k e r p e r s t a t e o r t o 15 t o 20 m inu te s p e r s t a t e i f a l l wish t o r e p o r t . The r e g i s t r a t i o n fe e w i l l In c lu d e two b r e a k f a s t s , two noon lunches and the even ing meal on June 27. Cos ts f o r b r e a k f a s t i s S3.95 e a ch , lunch S 3 .5 0 , and t h e e ven ing meal Is $ 6 .2 0 . For more i n f o rm a t i o n , p l e a s e c o n t a c t Or. Russ L o r e n z , TION P RGM Box 459 Mandan, ND 58554 701-663-6445 NORTH DAKOTA SPURGE TOURS D r. Rod Lym r e p o r te d th a t field t o u r s will be held a t t h r e e N .D .S .U . leafy s p u r g e r e s e a rc h s i te s in J u n e . The pub lic will be upd a te d on bo th biological and chemical con tro l d a ta . Those s chedu led to be p r e s e n t a r e : D r . Calvin Messersm ith (G roup l e a d e r ) . D r . Rober t C arlson (En tomology) , D r . Don Galitz (B o ta n y ) , D r . L a r ry L ittlefie ld (P lan t P a th o lo gy ) , and D r . Rod Lym (A g ronom y ) . The field d ay s will be held in Sheldon on J u n e 21 a t 7 :30 p .m . , Minot on J u n e 25 a t 7:30 p .m . and in D ickenson on Ju n e 26 a t 7:00 p .m . Those in t e r e s t e d in th e la te s t information on leafy s p u r g e con tro l a r e u rg e d to a t t e n d . MONTANA BIOLOGICAL CONTROL The flea b e e t l e , Ap thona f lava , was rece iv ed hy the USDA Rangeland In sec t Lab , Bozeman, in fall 1982. The in sec t is c u r r e n t l y being held in cold s to ra g e unti l f u r t h e r te s t in g is pe rfo rm ed on Eupho rb ia r o b u s ta . LEAFY SPURGE TOURS Mark y o u r c a le n d a r for th e summer leafy sp u r g e to u r s to be held in Montana. The to u r s shou ld be informative and fu n , with c u r r e n t u p d a te s on c u l tu r a l , chemical, a n d biological con tro l o f leafy s p u r g e . A te n ta t iv e s chedu le follows: J u n e 7 - 4:00 p .m . Petro leum Coun ty located a t Don Kimmel Ranch Con tac t : E v e re t t B rady 424-7571 Dave Phillips 538-3919 D a rry ld Kautzmann 323-2704 Ju n e 11 - Powell Coun ty Con tac t : Dave S t r e u f e r t 846-3680 Ju n e 14 - Roosevelt Coun ty Con tac t : Roger A sh ley 787-5312 Ju n e 15 - Valley C oun ty Con tac t : Rick S te l lf lug 228-2457 Verlin Koenig 228-2456 J u n e 21 - Cascade Coun ty Con tac t : Jim Freeman 727-2804 Doug John son 727-2804 Ju n e 22-24 STATE WEED FAIR - Toole Co. Con tac t : Kevin Laughlin 434-5351 S ep t . 5 - Fallon C oun ty Con tac t : Pam C a s t l e b e r r y 778-2891 SOUTH DAKOTA ECONOMICS OF SPURGE CONTROL IN PASTURE Dr. R ober t Nowierski re p o r te d th a t 1200 adu l t b e e t l e s , Oberea e r y t h r o c e p h a l a , were re lea sed in fou r field cages Tn Bozeman d u r in g 1982. P lan ts sampled in 1983 ind ica te th a t 40% to 50% of th e stems con ta in Oberea l a rv ae , however two y ea rs will be r e q u i r e d for larval deve lopment . S teve C y l l in g , a s s i s t a n t in th e P lan t S c ience D e p t . , S .D .S .U . re p o r te d t h a t sev e ra l he rb ic id e t r e a tm en ts were app lied for s ix g row ing s e a so n s to s p u r g e in fe s ted p a s t u r e s in e a s t c en t r a l S .D . The t r e a t ­ m en ts inc rea sed fo rage p roduc t ion up to 132 2800 Ib /A when compared to u n t r e a te d p lo t s . A dded r e t u r n ov e r t r e a tm en t co s ts r a n g ed from $26 .00/A b ene f i t to $18 .00/A loss from th e chemical a pp l ic a t ion s . T re a tm en ts which p ro v id ed th e most economically benefic ia l con tro l o f leafy s p u r g e a r e shown in T ab le I, Tab le I : It) a . I . / A time* X c o n t r o l added r e t u r n /A 2 , 4 - 0 e s t e r 3 . 0 S3F an n u a l l y 98 522 2 , 4 - 0 e s t e r 1 . 5 S&F a n n u a l l y 93 319 2 , 4 - 0 e s t e r 1 .5 S a n n u a l l y 75 317 2 , 4 - 0 e s t e r 3 . 0 S a n n u a l l y 8 2 315 Banvel ♦ 2 , 4 - 0 e s t e r 0 . 5 * 1 . 0 S a n n u a l l y 87 319 Tordon ♦ 2 , 4 - 0 e s t e r 0 .2 5 ♦ 1 . 5 S a n n u a l l y F a n n u a l l y 95 315 Roundup ♦ 2 , 4 - 0 e s t e r 3 . 0 ♦ 1.5 S f i r s t y e a r S su c c e ed i ng y e a r s 8 8 326 * S - s p r i n g a p p l i c a t i o n F - f a l l a p p l i c a t i o n 150 (0 .05 ) 15 3 9 Sp l i t t in g th e 2 , 4 - 0 app l ic a t ion s into s p r in g a n d fall t r e a tm en t was g en e ra l ly benefic ia l as compared to a s ing le s p r in g a p p l ic a t io n . H owever , when app lied with B anve l , th e b e s t con tro l was from a s ing le s p r in g app lica t ion a s a ta n k -m ix . The s in g le s p r in g R oundup app lica t ion a p p e a r e d to s u p p r e s s K en tu cky b lu e g r a s s g row th in th e p a s t u r e , t h e r e b y favo r ing w a rm -sea son g r a s s e s . In g e n e r a l , leafy s p u r g e con tro l was feas ib le in t h i s s t u d y , an d r e p e a t e d a p p l ic a t io n s o f h e rb ic id e w ere n e c e s s a r y to a ch ieve long - te rm c o n t ro l . CANADA WELCOME D r. Alec McCIay h a s r e c en t ly a c c e p te d a posi t ion a s weed s c ien t i s t re s p o n s ib le fo r b iocon tro l a t th e A lbe r ta Env ironmen ta l C e n t r e . D r . McCIay will b e condu c t in g fo l low -up s t u d ie s on r e ­ le a se s o f Ap thona an d Oberea e r y t h r o c e p h a l a . He will a lso be work ing with th e r e le a se o f add it iona l spec ies which a r e b e ing s c r e e n e d by th e CIBC in Sw i tz e r la n d . We welcome D r . McCIay to th e s t a f f in A lb e r t a , a nd look fo rw a rd to his c o n t r ib u t io n s to th e Leafy S p u rg e News. WYOMING NEWS ACTIVITY OF GROWTH REGULATORS S HERBICIDES ON LEAFY SPURGE Mr. Mark F e r r e l r e p o r te d on th e r e s u l t s o f a g r e e n h o u s e s c r e en in g s t u d y a n d field s tu d y of s e le c ted g row th r e g u l a ­ to r s an d h e rb i c id e s on leafy s p u r g e c o n t ro l . Banvel and To rdon were app lied to leafy s p u r g e a t 1/8 th e recommended r a t e s with th e following g row th r e g u la to r s : ACB-3034, a s y n th e t i c cy to k in in ; mixed c y to k in in s ; 2 ,4 -D ; g ibhe re l l ic a c id ; g ly p h o s a te ; n a p h th a Ianeacet ic ac id ; a n d PP333, an expe r im en ta l a n th ig ib b e r e l l in compound . Eva lua t ions of bo th th e field s t u d y a n d g r e e n h o u s e s c r e en in g s t u d y showed th a t th e g row th re g u la to r s were ine f fec t iv e in a id ing To rdon and Banvel in con tro l l ing leafy s p u r g e . PROGRAM EVALUATION George H it t le , s t a t e weed c o o rd in a to r , r e p o r te d on th e S ta te Evaluat ion Committee 's (SEC) review o f th e 1983 Leafy S p u rg e P rog ram . The S .E .C . members inc lude : G a ry O r r , Wyoming Weed 6 Pes t Counc il ; Jim Whalen, S ta te Land Office ; D r . Harold A lley , U n iv . o f WY; John O r to n , Commis­ s io n e r o f A g r ic u l tu r e ; M. F. Cowin, S ta te Board of A g r ic u l tu r e . The committee v is i t e d fou r c oun t ie s in 1983: L incoln , C ro ok , Weston and S h e r id an p lu s a t t e n d in g th e Leafy S p u rg e Symposium in S u nd an c e . The committee conc luded t h a t all 4 coun tie s w ere do ing a v e ry e f f ic ien t job o f con tro l l ing leafy s p u r g e . A pp ro x i ­ mately 3,237 a c r e s was in itia lly t r e a te d a nd 16,193 a c r e s was r e - t r e a t e d in 1983. A pp rox im a te ly 47, 641 a c r e s have b een ini t ia l ly t r e a t e d an d 61,986 a c r e s have been r e t r e a t e d from Ju ly I , 1978 th r u Dec. 31, 1983. * * * * * * * * For add it iona l in formation o r to be a d d ed to th e mailing l i s t , p lea se c o n ta c t : Ce les t ine Lacey Plant 6 Soil Sc i. D ep t . Montana S ta te U n iv e r s i ty Bozeman, MT 59717 133 Leafy Spurge News PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN, MONTANA 59717 VOLUME V Aug 1984 ISSUE 3 VUeLC1 J KNOtO X SHOULD TREAT THIS SPUt&E...., 6 u r I F I KILL LT H £ f£ , IT 'LL TOST __________ COrtQE tip OUEH YOtVDEH I MONTANA NEWS Pulling S p u rg e B ruce Maxwell r e p o r te d th a t a s t u d y to deve lop cu l tu ra l con tro l p ra c t ic e s for leafy s p u r g e was in i t ia ted in 1983. Machine pu ll ing was compared with mow­ in g , 2 , 4 - 0 (2 Ib /A ) , T o rdon ( .5 Ib /A ) , and 2 ,4 -D t r e a tm en ts following pulling an d mowing. R esu l ts from th e fall of 1 983 ind ica ted th a t s ing le s p r in g app lica ­ tion o f 2 ,4 -D amine a t 2 Ibs /A and machine pu ll ing with a fo llow-up t r ea tm en t of 2 ,4 -D to reg row th p rov ided the b e s t con tro l of leafy s p u r g e . The 2 ,4-D t r e a tm en t a lone p rov ided th e g r e a t e s t p e renn ia l g r a s s p ro d u c t io n , how ever , it was o b se rv ed th a t cows tend ed to g ra z e pu lled p lo ts more read i ly th an p lo ts t r e a te d with 2 ,4 -D . None o f th e machine pu l led , mowed, h e rb i c id e , o r combination t r e a tm en ts s ign if ic an t ly d ec re a s ed th e d en s i ty of leafy s p u r g e one y e a r a f t e r app lica t ion . Resu lts from th i s s t u d y showed th a t h and pull ing could be an e ffec t ive way to con tro l small in fe s ta t ion s o f leafy sp u r g e for one y e a r . Seed p roduc t io n can be elimi­ n a ted and reg row th is s ev e re ly s t u n te d which will slow th e advanc ing in fe s ta t ion . T h is method o f con tro l would be b e s t su i ted to small p a tche s a long w ate rways where h e rb ic id e u se is r e s t r i c t e d and where leafy s p u r g e seed p roduc t ion must be eliminated to p r e v e n t d isp e rsa l by w a te r . If a soil b o rn e p a thogen can be deve loped as a biological con tro l a g en t on leafy sp u rg e th e pu ll ing may be an e f fec t iv e way to inc rea se infec tion in th e p la n t . Moving On B . I. Maxwell re c en t ly completed h is MS d eg re e a t Montana S ta te U n iv e rs i ty . B ruce was a g r e a t a s s e t to ou r s p u r g e p rog ram in Montana an d we will miss h is ded ica t ion and h a rd work . B ruce p lans to a t t e n d O regon S ta te U n iv e r s i ty as a P h .D . c a n d id a te , work ing with D r. S teve Radosev ich . We will c on t inue to pub li sh r e s u l t s of th e r e s e a r c h t h a t B ruce co n ­ d u c te d in th e n e x t seve ra l n ew s le t te r s . B ru c e 's mailing a d d r e s s is: 129 NW 35th S t r e e t C o rva l l is , OR 97330 S p u rg e T ou rs Approx imate ly 435 people a t t e n d ed 9 t o u r s held in J u n e a n d J u ly . The t o u r s p rov id ed information on iden t if ica t ion and con tro l of both leafy s p u r g e and sp o t te d kn apw eed . A special t h a n k s to all of th e c oun ty a g e n t s , soil c on se rva t ion s e rv ic e p e r s o n n e l , soil c on se rv a t io n d i s t r i c t s , and weed su p e rv i s o r s who worked so h a rd to make th e s e to u r s a s u c c e s s . We also a p p re c i a te th e help and s u p p o r t o f Dow Chemical Company who sp o n so red the t o u r s . 134 Two fall t o u r s a r e p lanned th is y e a r : S e p t . 11 Fallon C oun ty C on tac t : Pam C a s t l e b e r r y 778-2891 S ep t . 12 Sw ee tg ra s s Coun ty Con tac t : Jim Roller! 932-5146 NORTH DAKOTA NEWS Success fu l Symposium Cong ra tu la t io n s to NDSU and USDA1 ARS for hos t ing an informative and en joyab le Leafy S p u rg e Symposium. The f i r s t d ay o f th e symposium was h ig h l ig h ted with r e s e a rc h r e p o r t s on c y to g e n e t i c s , chemotaxonomy, and biologi­ cal con tro l . The second day f e a tu r e d an u pda te on chemical con tro l o f s p u r g e and a b u s t o u r to s p u r g e problem a re a s and re s e a rc h p lo ts w es t o f D ickinson and in th e B ad land s . A special th a n k s to D r . Rod Lym1 D r . Russ Lorenz , D r . Cal M esse rsm ith1 D r . R obe r t Nowierski a nd o th e r s fo r p lann ing and o rgan iz ing th e symposium . Weed R esea rch N u r s e ry D r . Rod Lym re p o r te d th a t a p e r e n ­ nial weed con tro l a re a is be ing e s tab l i sh ed a t th e NDSU Exper im en t S ta t ion in Fa rgo . A 25 a c re a re a has been s e t a s ide for th e e s tab l i shm en t o f a leafy s p u r g e n u r s e r y a s well a s field b indw eed , perennia l sow th is t le and q u a c k g r a s s . T h e se p e r e n ­ nial weeds a r e be ing p lan ted to p rov ide an a rea w he re e xpe r im en ts r e q u i r in g daily ob se rv a t io n and t r e a tm en t can be con­ d u c te d . In th e p a s t su ch expe r im en ts were impractical b ecau se o f th e t rave l time and e x p en se . It will also p rov ide a s i te fo r con tro l led re lea se o f p a thogen s or in s e c ts th a t may become available fo r b io­ logical con tro l . It will t ak e app rox im a te ly 5 y e a r s to e s tab l i sh solid s t a n d s of th e p e r ­ ennia l weeds on the 25 a c r e s i te . Pathogen Update D r. L a r ry L it t le f ie ld , P lan t Patho logy D e p t . , NDSU1 r e p o r te d t h a t th e r e s u l t s of 1984 summer field s tu d ie s in North Dakota h ave no t been v e r y p rom is ing . Leafy s p u r g e p lo ts in 2 locations were inocu la ted with A lte rn a r ia tenu iss ima f . s p . e u p h o rb i a e , the fu n g u s which has g iven exce l len t contro l in g r e e n h o u s e s tu d ie s . V e ry l i t t le , if a n y , damage was done to leafy s p u r g e u n d e r field cond it ions by th e s e inocu la t ions . A new g r a d u a t e s t u d e n t will join th e p ro je c t in S ep tem be r . Two new tem p e ra tu re and hum idity con tro l led g row th chambe rs a r e now opera t iona l and s tu d ie s a r e u n d e r ­ way to induce muta t ions to h ig h e r v i ru le n c e in th e p a th og en . Now all th a t is n eeded is a b i t of coopera t ion from Euphorb ia e s u l a ! One b r i g h t no te is t h a t a Fusar ium sp . h a s been iso lated from dead Russ ian k n a p - w eed . T he re in may lie a po ten t ia l b iocon­ tro l fo r a n o th e r s e r io u s w eed . G reenhouse s tu d ie s will be made d u r in g the coming w in te r on t h a t h o s t -p a th o g en combination . Native In s e c ts on S pu rg e ! Joe Ju l ian r e c e n t ly completed h is MS d e g r e e a t NDSU. His m as te r s p rog ram was to co ndu c t a na t iv e in s e c t s u r v e y on leafy s p u r g e . The r e s u l t s o f h is r e s e a rc h showed th a t a l th ough n a t iv e in sec ts were no t o b se rv ed to c au se major damage to leafy s p u r g e , a few of th e in s e c ts may p lay a p a r t in con tro ll ing th e weed e i th e r d i r e c t ly o r in d i re c t ly . S p a rg a n o th is s u l fu re an a was found feeding on th e leaves and seed pods in v a r iou s p a r t s o f e a s t e r n ND. Th is in sec t is a p e s t of c e r t a in ag r ic u l tu ra l c ro p s in th e United S ta t e s so would not be a su i tab le in sec t fo r r e a r in g and re lease on leafy s p u r g e . It is poss ib le t h a t o th e r sp ec ie s o f th i s g e n u s would be more ho s t spec if ic to Euphorb ia p la n t s . The o th e r in s e c t found in g r e a t n um be r s was G luptina 135 a t r i v e n t r i s H orn , a flea bee t le closely re la ted to" th e g e n u s Apthona which has been imported and re lea sed on leafy s p u r g e in th e U .S . a n d C anada . The la rv ae o f th i s in sec t is be lieved to feed on th e roo ts o f Euphorb ia p lan t s a l though th e la rv ae was n e v e r found in th is s tu d y . The rem a inde r o f th e in s e c ts collected were e i t h e r n e c ta r f e e d e r s , po lyphagou s , o r inc iden ta l on leafy s p u r g e . WYOMING NEWS More Help! Carnal Heneidi, a Rh. D. c and id a te in Weed Science will be conduc t in g r e s e a rc h on th e a f f e c ts of h e rb ic id e s app lied a t v a r io u s s t a g e s o f g row th on leafy sp u rg e seed v iab i l i ty . Funds for S p u rg e D r . Mark Ferre l r e p o r te d th a t the U n iv e rs i ty of Wyoming has rece ived a $50,000 g r a n t from th e Wyoming D epa r t ­ ment o f A g r ic u l tu r e , e f fec t iv e April 1984, to con t inue r e s e a rc h on leafy s p u r g e . It is a coope ra t iv e a g re em en t in which the U n iv e rs i ty o f Wyoming will be re spon s ib le fo r I ) con tinua t ion o f th e rep e t i t iv e h e rb ic id e t r e a tm en t p ro g ram , 2) con t in u a ­ tion o f physica l p r a c t ic e s (mowing) p r io r to h e rb ic id e t r e a tm en t , 3) r e s e a rc h in g the u se o f l igh t r a t e s o f 2 , 1-D as a s e t - u p p r io r to t r e a tm en t with T o rd o n , 4) con­ tinua t ion o f eva lua tion o f fo rage p ro ­ duc t ion and c ro p to le rance to va r iou s h e rb i c id e s , and 5) con t inued monitoring o f env ironmen ta l cond it ions and p lan t b eh av io r . * * * * * * * * For add it iona l information o r to be added to th e mailing l i s t , p lease con ta c t : Ce les t ine Lacey P lan t 6 Soil S c i . Dept. Montana S ta te Un ive rs i ty Bozeman, MT 59717 136 Leafy Spurge News PLANT & SOIL SCILNCI DL PAHTML NT MONTANA STALL IINIVLITSILY BOZEMAN. MONTANA 59717 VOLUME V Dec 1984 ISSUE 4 HELL REX. I UOfIDER IF HE COULD CALL THIS BIOLOGICAL CONTROL ? \ MONTANA NEWS \ _________ Hawkmoth S p r e a d s S eve ra l r e l e a s e s o f th e s p u r g e hawkmoth Hyles e u p h o rb ia e L . , h av e o c c u r r e d in Montana s ince 1964. A t tem p ts to e s tab l i sh th i s biological con tro l a g e n t on leafy s p u r g e h av e been r e g a r d e d as only marg ina l ly s u c c e s s fu l . R ecen t s tu d ie s o f th i s in s e c t by Noah P o r i t z , g r a d u a t e s t u d e n t , MSU, ind ica te t h a t th e s p u r g e hawkmoth is well e s t a b l i s h e d n e a r Bozeman, MT. Noah 's s tu d ie s on th e popu la t ion dynam ics o f the hawkmoth h ave shown th a t a d u l t hawk- moths h av e d i s p e r s e d miles from th e i r initial r e le a se s i te s . Noah is also s t u d y in g r a t e s of feed ing an d deve lopment o f th e hawkmoth a t d i f f e r ­ e n t tem p e r a tu r e s in th e la bo ra to ry a n d f i e ld . He is a lso exam in ing morta l i ty and s u r v iv o r s h ip f a c to r s as well a s e x p and in g s tu d ie s on field popu la t ion dynamics o f th e s p u r g e hawkmoth for 1985. Hawkmoth Releases Seven new re lea se s i te s were e s t a b ­ lished on leafy s p u r g e in Montana. D r . R obe r t N ow ie rsk i , S tev e H a rv ey , and Noah P o r i tz , MSU, and Norman R ees , USDA Range In s e c t Lab w e re re spon s ib le fo r th e r e le a se of o v e r 1000 hawkmoth la rv ae in C a r t e r , G alla t in , R ich land , S ti l lw a te r , S w e e tg r a s s , and T e ton coun tie s in 1984. In itial o b s e rv a t io n s ind ica te th a t th e h aw k ­ moth is well e s t a b l i s h e d . Follow-up e v a lu ­ a t io n s will be c o ndu c te d in 1985. O berea Releases Mr. Norman Rees (USDA) r e p o r t s t h a t th e ro o t -b o r in g b e e t l e , O berea e r y t h r o c e p h a l a , which was re lea sed Tn G a l la t in , R ich land , a n d S t i l lw a te r c o u n t i e s , h a s shown its a b i l i ty to damage roo ts of leafy s p u r g e . T he a g e n t is e s ta b l i sh ed in Galla tin an d S t i l lw a te r co u n t ie s . Popu la ­ t io n s will be monitored in 1985 to confirm e s tab l i shm en t in R ich land Co. Contro l l ing Leafy S p u rg e Buds Scott N is s en , P h .D . c and id a te a t MSU, is c o nduc t in g g r e e n h o u s e and labo ra to ry s t u d i e s to de te rm ine f a c to r s re spon s ib le fo r b u d con tro l in leafy s p u r g e . The s t u d i e s h av e shown th a t d u r i n g f lowering an d in la te summer when d ay leng th s s h o r t e n , leafy s p u r g e roo t b u d s e n t e r a s t a te of do rm ancy which is no t b ro k en by simply removing th e a u x in s u p p l y . D uring th e s e p e r io d s th e in itia t ion o f a c t iv e g row th 137 r e q u i r e s a per iod o f ch il l ing tem pe ra ­ t u r e s . L abo ra to ry s tu d ie s ind ica te t h a t a p e r iod a s s h o r t as 8 d ay s a t 36°F is su f f ic ien t to b re ak th i s ty p e of do rm ancy . S ta r c h Utilization S co tt Nissen r e p o r te d th a t la rge s t a r c h r e s e r v e s a r e s to re d in bo th th e root sy s tem and la tex o f leafy s p u r g e . T h e ab i l i ty o f leafy s p u r g e to u ti lize s hoo t , r o o t , and la tex s t a r c h has been exam ined by g row ing p lan t s in th e d a rk . P re l im inary r e s u l t s ind ica te t h a t shoot and roo t s t a r c h levels d e c re a s e by 50% a f te r 11 d a y s w ithou t l ig h t , while la tex s t a r c h remains re la t iv e ly c o n s t a n t . It a p p e a r s t h a t la tex s t a r c h is no t a r e s e rv e of u ti l izab le c a r b o h y d r a t e . At th i s time the p u rp o s e o f th i s s t a r c h is u nknown . NORTH DAKOTA NEWS Associa tion Meets D r . Russ Lorenz and D r . Rod Lym r e p o r te d t h a t th e f i r s t annua l meeting of th e North Dakota Weed Contro l Association will be he ld on J a n u a r y 14, 1985, a t th e Kirkwood Motor In n , B ism arck , ND. The weed con tro l c on fe r en ce h a s b een formed to u n i t e weed con tro l o f f ic e rs in the 52 coun t ie s o f ND. Leafy s p u r g e con tro l will be empha­ s iz ed , b u t information will be p r e s e n te d on knapw eed a nd o th e r p e renn ia l w eeds . R epo r ts on s p r a y e r c a l ib r a t io n , r e g u la ­ t io n s , and weed s u r v e y s will a lso be p r e s e n t e d . S p e a k e r s on th e p rog ram inc lude r e s e a r c h e r s with USDA-ARS, Coop. Ex ten s ion S e rv i c e , A g r ic . Exp . S t n . , a n d NDSU. For more in fo rmat ion , p lease con tac t Wayne C o lb e rg , 600 W. Main E R ive rs id e , West F a rg o , ND 58078. His phone number is (701} 282-5487. N,HBLYN FBSI Euphorb ia Spec ie s Wanted D r. Alec McCIay r e p o r te d t h a t th e Commonwealth I n s t i t u te o f Bio Contro l a t Delemont, Sw i tz e r la n d , n e ed s seed o f a n umber o f Eupho rb ia sp ec ie s for u se in s c r e en in g t e s t s fo r po ten t ia l b iocontro l a g e n t s for leafy s p u r g e . If any r e a d e r s of th e Leafy S p u rg e News have seed o f th e s e sp ec ie s av a i lab le , o r know whe re th ey can b e ob ta in ed , p lea se con tac t A nd re C a ssm ann , CIBC Eu ropean S ta t io n , I Shemin (Jes C r i l lo n s , CH-2800 Delemont, Sw itz e r land . Your he lp is g r e a t ly a p p r e ­ c ia t e d . T he sp ec ie s n e ed ed a re : Eupho rb ia a n t i suph i l i t ic a E . corolla ta E. g rand ia fa ta E . maculata E. meloformis E. ob longa ta E. s e r p y Ilifolia E. t r ig ona E. wulfenii WYOMING NEWS Mowing S e ts Up H erb ic ide T re a tm en ts D r . Mark Ferre l l r e p o r te d th a t p lo ts w ere e s ta b l i s h ed n e a r H u le t t , WY to d e t e r ­ mine th e e f f e c t iv en e s s o f mowing p r io r to t r e a tm en t with h e rb i c id e s on con tro l l ing leafy s p u r g e shoot r e g row th . Leafy s p u r g e was mowed on Ju n e 30, 1982. H erb ic ide t r e a tm en ts were app lied on J u ly 21 , 1982. Leafy s p u r g e shoo t c o u n ts w e re ta k en in May, 1983 and 1984. Resu lts o f the t r e a tm en ts showed th a t T o rd on a t 0 .5 Ib/A and 2 ,4 -D LVE con ­ t in u e d to p rov ide good con tro l o f leafy s p u r g e 2 y e a r s following app lica t ion . 138 Additional s t u d ie s u s ing mowing p r io r to h e rb ic id e app l ic a t ion s a r e p lanned for 1985. Tab le I . T h e e f f e c ts o f mowing a s a s e t - u p t r e a tm en t p r io r to h e rb ic id e app li­ ca t ion . Herb ic ide Rate Ib/A t Contro l 1983 1984 Banvel 41_ 1.0 32 36 To rdon 22 K 0.5 86 75 2 , 1I-D LVE 1.0 91 85 Check 0 .0 0 0 Alley R e ti re s D r . Harold A lley , Ex tension Weed S c ien t is t a t th e U n iv e rs i ty o f Wyoming, r e t i r e d on November 30, 1989. His e x p e r t i s e a n d ded ica tion to weed sc ience will c e r t a in ly be missed in Wyoming; how eve r , Harold p lans to s e r v e as a c o n su l t a n t in the f u t u r e . Harold is c u r r e n t l y living in Casa G ra n d e , A rizona unti l April 1 985. We c e r ta in ly hope h is go lf game improves s u b s ta n t i a l l y . We'll miss y o u r words o f wisdom, Harold — Good Luck I * * * * * * * * * * * * * For add it iona l information o r to be added to th e mailing l i s t , p lease co n ta c t : C e les t ine Lacey P lan t 6 Soil S c i . D ep t. Montana S ta te U n ive rs i ty Bozeman, MT 59717 139 PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN. MONTANA 59717 Volume I OCTOBER 1983 ISSUE I G r e e t i n g s ! T h i s i s t h e f i r s t i s s u e o f t h e knapweed u p d a t e t h a t w i l l be p u b l i s h e d two t o t h r e e t im e s y e a r l y by t h e P l a n t and S o i l S c i e n c e D e p a r tm e n t a t Mon tana S t a t e U n i v e r s i t y . The p u r p o s e o f t h e n e w s l e t t e r i s t o h e l p c o o r d i n a t e r e s e a r c h e f f o r t s , s h a r e i n f o r m a t i o n , a r o u s e i n t e r e s t , and i n c r e a s e a w a r e n e s s o f s p o t t e d and d i f f u s e knapweed . We a p p r e c i a t e a ny c o n t r i b u t i o n s o r s u g g e s t i o n s t h a t you may h a v e . POOR OL' JEO. KNAPWEED COT HlS RANCH! I n T h i s I s s u e The Knapweed P ro b l em i n N o r t h A m e r ic a Mon tana U p d a t e : R a t e o f Knapweed S p r e a d Knapweed P h y t o t o x i n s C u r r e n t R e s e a r c h B r i t i s h C o lum b ia News Knapweed I n f e s t a t i o n s R e s e a r c h U pda te Econom ic L o s s f rom Knapweed The Knapweed S i t u a t i o n : I d a h o O regon W a sh in g to n S p o t t e d and D i f f u s e Knapweed i n N o r t h A m e r i c a Jo h n n y C a sh , t h e c o u n t r y w e s t e r n s i n g ­ e r h a s a song w he re h e s t a t e s t h a t t h e "wa­ t e r i s 5 f e e t h i g h and r i s i n ' . " I f he was a s k e d how t h e knapweed w as d o in g i n N o r t h A m e r i c a , he wou ld p r o b a b l y s a y " i t ' s i n ­ f e s t e d 8 m i l l i o n a c r e s — and i n f e s t i n ' . " S p o t t e d and D i f f u s e knapweed was i n ­ t r o d u c e d t o N o r t h A m e r ic a f rom t h e E u r a s i a n s t e p p e g r a s s l a n d s i n t h e e a r l y 1 9 0 0 ' s a nd h a s s p r e a d r a p i d l y o v e r r a n g e l a n d s i n B r i t i s h C o lum b ia , M o n ta n a , I d a h o , O re g o n , a n d W a s h in g to n . T h e s e knapweeds a r e c a u s ­ i n g s u b s t a n t i a l l o s s e s t o t h e l i v e s t o c k i n d u s t r y , e n v i r o n m e n t a l d e t e r i o r a t i o n and u n d e t e rm in e d r e d u c t i o n i n r e c r e a t i o n a l v a l ­ u e , a e s t h e t i c s , q u a l i t y o f w i l d l i f e h a b i t a t and p r o p e r t y v a l u e s . On ly i n r e c e n t y e a r s h a v e s i g n i f i c a n t e f f o r t s b e e n made t o c o n ­ t a i n i t s s p r e a d . The knapweed s a r e h i g h l y c o m p e t i t i v e p l a n t s w h ich a r e c a p a b l e o f i n v a d i n g r a n g e - l a n d s t o t h e n e a r e x c l u s i o n o f d e s i r a b l e f o r a g e . R e d u c t io n i n f o r a g e o f 90% o r more i s common on s e v e r e l y i n f e s t e d s i t e s . T h e s e weeds a r e e x t r e m e l y a g g r e s s i v e , d r o u g h t t o l e r a n t , and v e r y p r o l i f i c , w i t h a h i g h r a t e o f s e e d v i a b i l i t y . S i n c e k n ap ­ weed i s n o t n a t i v e t o N o r t h A m e r i c a , t h e r e a r e no n a t i v e e n em ie s o r p a r a s i t e s t o k e ep i t i n c h e c k . T h e s e f a c t o r s e n a b l e knapweed t o fo rm l a r g e , d e n s e i n f e s t a t i o n s and s p r e a d r a p i d l y . Knapweed S p r e a d s h e r b i c i d e s , a h i g h l e v e l o f p u b l i c aw a r e ­ n e s s and e f f e c t i v e b i o l o g i c a l c o n t r o l . Economic Im p a c t Roy C r a n s t o n e s t i m a t e s t h a t t h e l o s s e s i n s t o c k i n g r a t e on B .C . r a n g e l a n d s due t o kn apweed a r e 3 2 ,0 0 0 A n im a l U n i t Mon th s (A .U .M . ) . T h i s f i g u r e was o b t a i n e d by u s i n g d a t a i n T a b l e I . W ith t h e v a l u e o f a n A.U.M. a t $ 1 0 , t h i s r e p r e s e n t s a l o s s o f $ 3 2 0 , 0 0 0 a n n u a l l y i n f o r a g e p r o d u c t i o n . Howeve r , by u s i n g a f o r a g e - t o - b e e f c o n v e r ­ s i o n o f 1 2 : 1 , t h e l o s s i n b e e f v a l u e a t t h e f a rm g a t e i s o v e r $ 1 . 5 m i l l i o n a n n u a l l y . I f knapweed s p r e a d o v e r t h e p r o j e c t e d 1 . 1 m i l l i o n h a . o f r a n g e l a n d , t h e p o t e n t i a l l o s s i n a n n u a l f a rm g a t e b e e f v a l u e would b e n e a r l y $41 m i l l i o n b a s e d on 1982 p r i c e s . Table I : Loss in Animal Uni t Months (A.U.M.) Due t o Knapweed Average S to ck ing Rate on Gr as s - Average S to ck ing Rat e on l a n d and Ponderosa Pine S i t e s in Knapweed I n f e s t e d Range Good Cond it i o n (No Knapweed) Fo rage P rodu c t i o n 560 kg /ha 112 kg/ha A.U.M." 1 . 0 ha/A .U.M . 5 . 0 h e / A . U . M . * Based on 63% u t i l i z a t i o n o f fo r ag e C u r r e n t R e s e a r c h R e s e a r c h on t h e knapweed s p e c i e s c u r ­ r e n t l y u nd e rw ay i n B .C . and w h ic h w i l l be r e p o r t e d on i n f u t u r e i s s u e s i n c l u d e : 1 . Use o f M ic ro -Max U l t r a -L o w Volume s p r a y n o z z l e s 2 . B i o l o g i c a l c o n t r o l 3 . A l t e r n a t i v e s t o p i c l o r a m 4 . S o i l s e e d b a n k l o n g e v i t y 5 . Knapweed p h e n o lo g y 6 . LANDSTAT im ag e r y t o map knapweed i n f e s t a t i o n 7 . A l l e l o p a t h y S t e v e Dewey, E x t e n s i o n Weed S p e c i a l ­ i s t , c o n d u c t e d a t e l e p h o n e - m a i l s u r v e y t o d e t e rm i n e l o c a t i o n s and s i z e o f i n f e s t a ­ t i o n s o f n o x i o u s w eed s i n I d a h o . R u s s i a n knapweed h a s b e e n r e p o r t e d i n 25 c o u n t i e s . D i f f u s e knapweed was r e p o r t e d i n 15 c o u n t ­ i e s a nd s p o t t e d knapweed i n 24 c o u n t i e s . A l t h o u g h t o t a l a c r e s i n f e s t e d h a v e n o t b e en q u a n t i f i e d , e s t i m a t e s i n c l u d e 3 0 0 ,0 0 0 a c r e s o f s p o t t e d k n a pw e e d , 2 5 , 0 0 0 a c r e s o f d i f ­ f u s e knapweed and a b o u t 5 0 ,0 0 0 a c r e s o f R u s s i a n knapweed i n s o u t h e r n I d a h o . OREGON R ob e r t H awkes , S u p e r v i s o r o f t h e Weed C o n t r o l P ro g r am , r e p o r t e d t h a t t h e k n a p ­ w eed s a r e a s e r i o u s p r o b l em i n O re g o n . D i f f u s e knapweed i s t h e m os t p r e v a l e n t , o c c u p y i n g a b o u t 5 m i l l i o n a c r e s i n t h e n o r t h e a s t q u a r t e r o f t h e s t a t e . S p o t t e d knapweed i n f e s t s a b o u t 2 0 , 0 0 0 a c r e s , b u t i s s p r e a d i n g a t a r a p i d r a t e i n some a r e a s . A c h e m i c a l c o n t r o l p r o g ram i s b e i n g u s e d t o e l i m i n a t e new i n f e s t a t i o n s w h i l e t h e y a r e s t i l l s m a l l . T h i s i n v o l v e s a r e a s w e s t o f t h e C a s c a d e M o u n t a in s and s o u t h c e n t r a l and s o u t h e a s t e r n O re g o n . B i o l o g i ­ c a l c o n t r o l m e th o d s a r e b e i n g u t i l i z e d i n t h e n o r t h e a s t e r n p o r t i o n o f t h e s t a t e . WASHINGTON The Knapweed S i t u a t i o n Ben R oche , Range S p e c i a l i s t a t WSU r e p o r t e d t h a t t h e r e a r e a b o u t 12 m i l l i o n a c r e s o f t im b e r e d and n o n - t im b e r e d r a n g e - l a n d i n W a s h in g to n . A 1982 s u r v e y showed t h a t 39% o f t h e n o n - t im b e r e d r a n g e was i n p o o r c o n d i t i o n and 30% was i n f a i r c o n d i ­ t i o n . The r a n g e c o n d i t i o n h a s b e e n low e r e d by m i s u s e , o v e r u s e , and t h e r e s u l t i n g i n ­ c r e a s e i n l e s s d e s i r a b l e n a t i v e s p e c i e s ( b i g s a g e ) o r i n v a s i o n s o f e x o t i c g r a s s e s ( c h e a t g r a s s and m edusa h e a d ) . Now t h e r e i s a new p r o b lem t h a t m akes e v e r y t h i n g w e 'v e e x p e r i e n c e d i n r a n g e r e h a ­ b i l i t a t i o n m i l d by c o m p a r i s o n . T h i s i s t h e i n t r o d u c t i o n and s p r e a d o f d i f f u s e and s p o t ­ t e d knapweed and y e l l o w s t a r t h i s t l e . R e c e n t s u r v e y s s u g g e s t a n n o n - t im b e r e d a c r e a g e o f I , 1 4 6 ,7 4 0 a c r e s o f d i f f u s e a nd s p o t t e d knapweed and 1 7 9 ,3 1 7 a c r e s o f y e l ­ low s t a r t h i s t l e . R e s e a r c h on h e r b i c i d e s and h e r b i c i d e s i n c o m b in a t i o n w i t h N f e r t i l i z e r i s c u r ­ r e n t l y b e i n g c o n d u c t e d . A d e t a i l e d r e p o r t o f t h i s r e s e a r c h w i l l f o l l o w i n f u t u r e i s ­ s u e s . * * * * * F o r more i n f o r m a t i o n o r t o be added t o t h e m a i l i n g l i s t , c o n t a c t : C e l e s t i n e L a c e y P l a n t & S o i l S c i e n c e D e p a r tm e n t Montana S t a t e U n i v e r s i t y Bozeman, MT 59717 141 MONTANA UPDATE: The Knapweed T a k e - o v e r D r . J o h n L a c e y , r a n g e s p e c i a l i s t a t MSU, e s t i m a t e s t h a t t h e r e a r e a b o u t 2 m i l l i o n a c r e s o f s p o t t e d and d i f f u s e k n a p ­ weed i n M on ta n a . H ow eve r , he f e e l s t h a t t h e s e r i o u s n e s s o f t h e p r o b lem c a n n o t b e a p p r e c i a t e d u n t i l t h e r a t e o f knapweed s p r e a d i s known. He p r o p o s e s t h a t t h e r a t e o f s p r e a d c a n be e s t im a t e d w i t h t h e com­ p o u n d i n g f o rm u l a t h a t b a n k e r s u s e t o " c o n ­ v e r t p r e s e n t v a l u e s t o a f u t u r e s um :" Vn=Vo ( l + i ) n Vn = v a l u e a f t e r " n " y e a r s ; Vo = p r e s e n t v a l u e ; n = number o f y e a r s , and i = r a t e o f s p r e a d . The compound ing f o rm u l a i s b a s i c t o c a l c u l a t i n g t h e v a l u e t o w h ic h am oun ts o f money d e p o s i t e d a t i n t e r e s t t o d a y w i l l g row t o by some f u t u r e d a t e . Knapweed a p p e a r s t o i n c r e a s e t h e same way . I f we a s sum e t h a t t h e r e was o n l y I a c r e o f knapweed i n Mon tana i n 1920 , and 2 m i l l i o n a c r e s i n 1980 , we c a n c a l c u l a t e t h e r a t e o f s p r e a d by u s i n g t h e compound ing f o rm u l a : 2 , 0 0 0 , 0 0 0 = I ( l = i ) 60 By s o l v i n g f o r " i " i t a p p e a r s t h a t knapweed h a s b e e n s p r e a d i n g a t a n a n n u a l r a t e o f 27%! I f we a s sume t h a t t h i s r a t e o f s p r e a d c o n t i n u e s i t w i l l t a k e o n l y a b o u t 14 y e a r s b e f o r e 60 m i l l i o n a c r e s o f r a n g e l a n d a r e i n f e s t e d w i t h s p o t t e d knapweed i n M on ta n a . T h i s c l e a r l y i n d i c a t e s t h a t l a n d man­ a g e r s , e c o n o m i s t s , r e s e a r c h e r s , and l e g i s ­ l a t o r s m u s t p l a c e m o re em p h a s i s on k n a p ­ w e e d . Economic b e n e f i t s o f a c o n t r o l p r o ­ g ram s h o u l d i n c l u d e t h e v a l u e o f r e s o u r c e p r o t e c t i o n a s w e l l a s f o r a g e i n c r e a s e s . F h y t o t o x i n s S t u d i e d D r . R i c k K e l s e y , D e p t , o f C h e m i s t r y a t t h e U n i v e r s i t y o f M on tana i n M i s s o u l a , r e ­ c e n t l y r e c e i v e d a r e s e a r c h award o f $ 1 0 5 ,0 0 0 . The award w i l l b e u s e d t o c o n ­ d u c t a s t u d y e n t i t l e d " S p o t t e d Knapweed P h y t o t o x i n s and T h e i r E c o l o g i c a l S i g n i f i ­ c a n c e . " The g o a l i s t o g a t h e r i n f o r m a t i o n on t h e n a t u r a l p h y t o t o x i n s p r o d u c e d by s p o t ­ t e d knapweed and e v a l u a t e t h e i r c o n t r i b u ­ t i o n t o t h e e c o l o g i c a l s u c c e s s o f t h e s e p l a n t s . T h i s w i l l im p ro v e o u r u n d e r s t a n d ­ i n g o f knapweed b i o l o g y and s h o u ld h e l p i n t h e d e v e lo pm en t o f a n e c o n o m i c a l c o n t r o l . S i n c e t h e s t u d y b e g an i n M a rch , o n e compound h a s b e e n i s o l a t e d and i d e n t i f i e d . I t i s a m a jo r componen t o f t h e g r e e n t i s s u e a n d i n h i b i t s t h e g e r m i n a t i o n o f c r e s t e d w h e a t g r a s s and l e t t u c e s e e d i n t h e l a b . At l o w e r c o n c e n t r a t i o n s l e t t u c e s e e d s w i l l g e r m i n a t e , b u t t h e r o o t g r ow th i s s e v e r e l y r e t a r d e d . The e f f e c t s on b l u e b u n c h w h e a t - g r a s s , I d a h o f e s c u e , r o u g h f e s c u e , and p r a i ­ r i e j u n e g r a s s i s b e i n g t e s t e d w i t h s e e d s c o l l e c t e d t h i s summer. T e c h n i q u e s a r e b e ­ i n g d e v e l o p e d t o m e a s u r e t h e c o n c e n t r a t i o n o f t h i s p h y t o t o x i n i n t h e p l a n t and s u r ­ r o u n d i n g s o i l . C u r r e n t R e s e a r c h R e s e a r c h c u r r e n t l y b e i n g c o n d u c t e d on s p o t t e d knapweed i n M on tana i n c l u d e s : 1 . B i o l o g i c a l c o n t r o l 2 . H e r b i c i d e c o n t r o l 3 . P r e d i c t i n g weed m i g r a t i o n s 4 . S e ed l o n g e v i t y s t u d i e s 5 . A l l e l o p a t h y s t u d i e s T h i s r e s e a r c h w i l l b e r e p o r t e d on i n f u t u r e i s s u e s . BRITISH COLUMBIA Knapweed S p r e a d s Roy C r a n s t o n , weed s p e c i a l i s t f o r B .C . , e s t i m a t e s t h a t o v e r 4 0 , 0 0 0 h a . ( 1 0 0 , 0 0 0 a c . ) o f B .C . r a n g e l a n d s a r e c u r ­ r e n t l y i n f e s t e d w i t h k n apw ee d . T h e r e i s a p o t e n t i a l f o r s p r e a d t o o v e r I m i l l i o n h a . ( 2 . 5 m i l l i o n a c . ) o f op en g r a s s l a n d and a n u n d e t e rm i n e d amount o f o p en f o r e s t r a n g e . He f e e l s t h a t t h e u l t i m a t e s o l u t i o n t o t h e knapweed p r o b l em i n B .C . d o e s n o t l i e i n m a s s i v e a p p l i c a t i o n o f h e r b i c i d e s . T h i s i s m a i n l y b e c a u s e o f t h e i n a c c e s s i b i l i t y o f many i n f e s t a t i o n s , t h e h i g h c o s t o f h e r b i ­ c i d e s and a p p l i c a t i o n , t h e p r o l i f i c n a t u r e o f knapw eed , and t h e r e s t r i c t i v e l e g i s l a ­ t i o n t o p r o t e c t t h e e n v i r o n m e n t . The l o n g - t e r m s o l u t i o n t o kn apweed c o n t r o l i n B .C . w i l l b e a c o m b i n a t i o n o f p r o p e r g r a z i n g m an ag em en t , j u d i c i o u s u s e o f 142 knapweed update PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN. MONTANA 59717 VOLUME Il JANUARY 1984 ISSUE I T h is i s su e o f th e Knapweed Update will f e a tu r e th e s t a tu s o f biological con tro l of sp o t te d and d i f fu se knapweed in th e United S ta te s and Canada . KNAPWEED SYMPOSIUM The b ig g e s t knapweed e v e n t of the y e a r is be ing held on April 3 and 4 a t th e S h e ra to n Hotel in G rea t Falls , Montana. The p u rp o s e o f th e sympo­ sium is to p r e s e n t new r e s e a rc h d a ta on th e ecology and management of the knapweeds and d ev ise s t r a te g i e s to implement new contro l te chno logy . T he symposium is s pon so red by Montana S ta te Univ . P lant and Soil Science D e p t . , Montana Coop. Ext. S e rv ic e , Western Montana Weed Council , Montana Knapweed Action Committee, and Lewis and C lark and Lincoln Co. C onse rva t ion D is t r ic t s . Anyone w ishing to p r e s e n t a p ap e r shou ld subm it th e t i t le to D r . John Lacey , Ex t . Range S pec ia l is t , 221 Linfield ha l l , Montana S ta te U n iv . , Bozeman, MT 59717-0002 by J a n u a ry 25, 1984. Additional information is ava ilab le from D r. P e te r K . Fay , Plant and Soil Science D e p t . , Montana S ta te U n i v . , Bozeman, MT 59717-0002 (406)994-5061. O N E T H I N G ' S F O R S U R E M A V I S , T H E R E ' S P L E N T Y T O E A T ! INTRODUCTION Biological con tro l is th e u se of n a tu ra l enemies ( i n s e c t s , d i s e a s e s , and o th e r o rgan ism s) to con tro l weed sp e c ie s . The ob jec t ive o f biological con tro l is not e rad ica t ion of w eeds , b u t r a t h e r th e reduc t ion and s tab il iza t ion of th e weed popula t ion below economic t h r e s h - h o l d s . Because th e knapw eeds were in t ro du c ed to N . America , th e r e a re v e r y few na t ive in s e c ts o r d is e a se s th a t a t t a c k th e p la n t s . T h u s re s e a rch s c i e n t i s t s have been in t roduc ing o rg a ­ nisms for the biological con tro l of th e se w eeds . 143 Jim S to r y , Western Montana A g r icu l tu ra l R esea rch C en te r a t C o rva l l is , and D r . R obe r t Nowierski, M .S .U . , a r e work ing coopera t ive ly on th e biological con tro l p rog ram for s p o t te d and d i f fu se knapweed in Montana. D uring th e p a s t 10 y e a r s fou r sp ec ie s of in s e c ts have been re lea sed on th e s e two knapweed sp e c ie s . T he s t a t u s o f th e in s e c ts follows: U ropho ra a f f in i s : T h is small fly a t t a c k s the f lower b u d s o f sp o t te d and d if fu se knapw eed . The fly la rv ae cause the p lan t to form "galls" in th e flower b ud s which reduce seed p ro duc t io n . Re­ leases of the fly w ere made a t 15 s i te s d u r in g 1973-1977 in w e s te rn Montana. The fly became e s tab l i sh ed and has d i s p e r s e d to a r a d iu s o f a t leas t 5 miles a t all s i t e s . A fou r y e a r s tu d y a t 5 s i te s showed th a t th e p e rc e n t knapweed se edh e ad s in fe s ted with th e fly and the a v e r a g e number of ga l ls p e r seed head in c re a sed s ig n if ic an t ly . In 1981, th e p e r c e n t o f fly in fe s ted seed h eads ra n g ed from 63-95%. Large popu la t ions o f th e fly now o ccu r a t re lease s i te s n e a r B u t te , T ow n send , L iv ings ton , G ey se r , and Roundup . U ropho ra q u a d r i f a s c i a t a : Th is in sec t is a n o th e r giTT f ly , c losely re la ted to U. a f f in i s . T h is f ly , in t ro du ced in B r i t ish Columbia, Canada in 1972, is m ig ra t ing into w e s te rn Montana a t a rap id r a t e . In c o n t r a s t to U . af f in is which has only one g en e ra t io n p e r y e a r , U. q u a d r i - fasc ia ta has 2 g e n e ra t io n s p e r y e a r , forms th in n e r g a l l s , and a t t a c k s more m a tu re flower b u d s th an LU a f f in i s . Because th e two fl ies a t t a ck the flower b u d s a t d i f f e r e n t p lan t g row th s t a t e s , th ey complement each o th e r in th e i r a t t a c k of th e seed head and spo t ted knapweed seed r e d u c t io n s of 95% have been r e p o r te d in a re a s where both fl ies a r e well e s ta b l i sh ed . Metzneria p a u c ip u n c te l l a : The la rvae of th is small moth a t t a c k s th e flower b ud s o f s p o t te d knapw eed . Four re leases of th i s moth were made in Montana d u r in g 1980-1983. Data col­ lec ted in 1982 showed 11.2% in fes ted seed h ead s in a field cage compared to only 1.0% a t a f ie ld - r e le a s e a re a . S tud ie s a r e c u r r e n t l y being con ­ d u c te d to de te rm ine th e compatib ili ty be tween th is moth a nd th e seed head f ly . S ph enop te r a ju g o s la v ic a : Th is bee t le mines th e roo ts of EJTTfuse knapw eed . Small numbers of th e bee t le were r e ­ leased in 1983; s t a t u s of th e beetle has no t y e t been d e te rm in ed . CURRENT STUDIES Severa l s t u d ie s re la t ing to bio­ con tro l of s p o t te d knapweed a r e c u r r e n t l y u nde rw ay : 1. Fly impact s t u d y : T h is s t u d y ( in i t ia ted in 1983) will measu re the to tal impact of th e 2 seed head fl ies on th e seed p ro duc t io n , b iomass , and number of flower h e a d s / p l a n t on spo t ted k n a p ­ weed. 2. F ly -h e rb ic id e in teg ra t io n s t u d y : A s tu d y was in i t ia ted in 1983 to de te rm ine if LU aff in is and th e he rb ic id e 2 ,4 -D could be u sed in an in t e g ra t e d contro l p rog ram a g a in s t s p o t te d knapw eed . T h e ob jec t ive is to de te rm ine the op t i ­ mum timing of 2 ,4 -D app lica t ions to ach ieve th e maximum contro l of spo t ted knapweed with a minimal e ffec t on the fly popu la t ion . 3. S po tted knapweed d e g re e - d a y s t u d y : The ob jec t ive o f th e s tu d y is to de te rm ine the re la tion of t em pe ra tu re to deve lopment of s p o t te d knapweed . Th is information will b e u sed to develop g row th models of th e p lan t and p red ic t optimum times fo r b iocontro l a g en t re lea se . NEW INSECTS! P rep a ra t io n s a r e be ing made for th e re lease of two roo t mining moths in Montana on sp o t te d an d d if fu se k n a p ­ weed in 1984 o r 1985. The la rvae feed in th e roo ts of small ro s e t t e s which commonly r e s u l t s in th e d ea th of the p lan t . 144 Bob Hawkes r e p o r te d th a t in th e n o r t h e a s t e r n port ion of O regon , chemi­ cal con tro l o f s p o t te d and d if fu se knapweed does no t a p p e a r feas ib le , t h u s biological con tro l a g e n t s a re be ing u s e d . Both spec ies of seed head gall f l ies , U ropho ra a ff in is a n d U . q u a d r i - fasc ia ta a r e w idesp read a nd r e d i s t r i b u - t ions a r e be ing made to new a re a s . The roo t b o r ing b ee t le , S phenop te r a ju g o s la v ic a , is well e s tab l i sh ed on d i f fu se knapweed a t one s i te in Morrow coun ty and will be r e d i s t r ib u t e d in 1984. The moth Metznaria p au c ipunc - tella is e s tab l i sh ed on sp o t te d knapweed a t one s i te in D eschu te s coun ty and p lans a r e be ing made to re loca te some o f them in th e n e a r f u t u r e . It is still too e a r ly to see much e f fec t on the knapweed p lan ts from th e s e l a t te r two in s e c ts . WASHINGTON Dr. G. L. P ip e r , W .S .U . , r e p o r te d t h a t th e knapweeds in fes t a bou t 1.5 million a c r e s in Washing ton , with d i f fu se knapweed being the p redom inan t sp ec ie s . In 1974, an a c t iv e biological con­ tro l p rog ram was in i t ia ted with th e re lease o f th e seed head fly U rophora a f f in i s . T h is fly a t t a c k s bo th spo t ted and d i f fu se knapweed in fes t ing up to 90% of th e h ead s p roduced by a p lan t . The fly is e s tab l i sh ed in n ine cen tra l and e a s t e r n Washington c oun t ie s . A no th e r seed head gall-fo rm ing f ly , U. q u ad r i f a sc ia ta was f i r s t d i s ­ cove red in th e s t a te in 1979. The fly invaded Washington from B rit ish Columbia. Th is b ioagen t now o ccu rs in all c oun t ie s e a s t o f th e Cascade M ts. T h is fly completes two g en e ra t io n s a y e a r and is a much b e t t e r colonizer of s p o t te d and d i f fu se knapweed in fes ted s i tes th an is U. a f f in i s . Over 90% of th e flower h ead s may be a t t a c k ed and up to 15 galls h ave been found in a s ing le h ead . The moth , Metzneria pauc ipunc te lla was re leased in 1981 a t th r e e s i tes in e a s t e r n Washington for th e contro l of sp o t te d knapw eed . T he moth e s t a b ­ lished ea s i ly , b u t is inc rea s ing its n umbers slowly a t th e re lease s i te s . Normally only one o r two la rvae develop p e r h e ad . It is too e a r ly to a s s e s s th e b iocontro l po ten t ia l of M e tzne r ia . The b ee t l e , Sphenop te ra ju go s lav ic a , whose la rv ae feed m th e roo ts of d if fu se kn apw eed , was re leased in 1983 a t a s i te in Okanogan Coun ty . Call formation by th e la rvae s t ru c tu r a l l y weaken the roo t and reduce p lan t v ig o r , p a r t ic u la r ly among p lan ts occupy ing low ra infa ll a r e a s . New In sec ts New biological con tro l a g e n t s sch edu led for re lea se inc lude the d i f ­ fu se knapweed roo t - fe ed ing moths Pe loch r is ta medullana ( 1984) and P te ro - Ionche in sp e r sa (1985) and the spo t ted knapweed ro o t - in f e s t in g moth Agape te zoegana (1985). S tu d ie s a re also being c a r r i e d ou t in Europe p re s e n t ly to find and eva lua te add it iona l enemies ( in ­ s e c t s , m ites , p a th o g en s ) which may be su i tab le for in t roduc t io n into the s ta te in th e f u tu r e . D r. Joe M cCaff rey , Univ. of Idaho , re p o r te d on b iocontro l ac tiv i t ie s on th e knapweeds in Idaho . Activ i t ies d u r i n g 1983: 1. R ed is t r ib u t io n o f th e two spec ie s of ga l l - fo rm ing fl ies IJ. aff in is and U . q u ad r i f a s c ia ta to additional spottecT knapweed s i te s . 2. Monitored e s tab l i shm en t and popula t ion b u i ld -u p o f th e moth Metzer- a r ia pauc ipunc te l la on spo t ted kn ap ­ weed. 3. Developed p re l im ina ry p h e n ­ ology model d e s c r ib in g f i r s t g ene ra t ion a d u l t emergence of th e two 145 ga ll - fo rm ing fl ies from sp o t te d knapweed seed h ead s . 4 . Under took field and lab s tu d ie s to e v a lu ta te th e e f f e c ts of picloram and 2 ,4 -D on U ropho ra s p p . on spo t ted knapw eed . 5. C reg Wheeler, a g r a d s t u d e n t , c on t inued b io logical , ecological and b ehav io ra l s t u d ie s on two s p id e r s , D ictyna major and D. c o lo r a d en s i s , th a t a r e po ten t ia l ly Im p o r ta n t mortality fac to rs a f fec t ing th e ga ll -fo rm ing flies on kn apw eed s . The th e s is will be completed by Ju n e 1984. New Work for 1984 1 . C on tinue r e d i s t r ib u t io n e f fo r t s o f s eed head fl ies. 2. In i t ia te biological s tu d ie s on th e moth Metzneria to de te rm ine its compatib i l i ty with U rophora sp p . 3. Eva lua te fly s y n c h ro n y with s p o t te d knapweed pheno logy . 4. Monitor field p lo ts p rev iou s ly t r e a t e d with To rdon and 2 ,4 -D to ev a lu a te long te rm a f f e c ts re la t ing to r e - e s ta b l i s hm en t o f U ropho ra sp ec ie s . 5. Complete field s u r v e y o f a r t h r o p o d s a s soc ia ted with s po t ted kn apw eed , con t inue with d i f fu se k n ap ­ weed. 6. E lizabeth Vog t , a new s t u d e n t will in i t ia te a s t u d y o f th e nu tr i t iona l r e q u i rem en ts of U ropho ra s p p . a d u l t s . CANADA D rs . P e te r H a rr i s and J . H. Meyers r e p o r te d on th e re lease of fou r in s e c ts in C anada . T he s t a tu s on th e re lease of th e s e in s e c ts follows. U ropho ra a f f in i s : T h is seed head fly was re lea sed m 1970 and has e s t a b ­ lished on bo th spo t ted and d if fu se knapweed in B r i t i sh Columbia and Q uebec . In H as t ing s C oun ty , O n ta r io , ga lls were found th e y e a r following r e le a se , b u t s u b s e q u e n t heavy g raz ing d e s t r o y e d most of th e knapweed h ead s . U ropho ra q u a d r i f a s c i a ta : Popula t ions of th i s seed head fly Inc reased rap id ly a f t e r re lease in 1972, b u t has s ince dec lined to low num be r s a t o r ig inal re le a se s i t e s . U. q u ad r i fa sc ia ta h a s s p r e a d more widely and rap id ly th an LU aff in is and has been found on remote knapweed s t a n d s in B .C . The immediate e f fe c t of bo th th e seed head fl ies on th e s t u d y s i te a t Kamloops, B .C . h a s been a decline in seed p roduc t ion from abou t 25,000 to 1 ,500 /m 2 and a r edu c t io n in th e biomass of th e weed , b u t th e number of p lan ts p e r u n i t a rea has remained th e same. Metzneriaci p a u c ip u n c te l l a : Adult moths were re leased in 1973 and 1974 a t C a s te lg a r and Westwold , B .C . No moths have been r e cove red from Cas te l - g a r . However Westwold moth popu ­ la t ions had sp re ad to a r ad iu s of .5 km by 1981. The e ffec t o f t h i s moth on sp o t te d knapweed was less th an expec ted from European s tu d ie s as a d i f fe re n t species of knapweed a p p e a r s to be involved in B .C . Also, th e ov e rw in te r in g la rvae a t Westwold, B .C . h av e su f f e r e d a per iod ic la rge and unexp la in ed w in te r m o r ta l i ty . The ab i l i ty o f both th is moth and th e fly LI. q u ad r i f a s c ia ta to s u rv iv e in co lde r paFts of th e Canadian p ra i r ie s is doub tfu l . S ph enop te r a ju g o s la v ic a : Releases of th i s bee tle were made a t C rand fo rk s an d White Lake, B .C . in 1976. No s u r v iv o r s were found a t G ra n d fo rk s , b u t th e colony a t White Lake inc rea sed to in fe s t 25-50% of th e ro s e t t e s within a 250 meter r ad iu s in 1981, and ove r I of th e flowering p lan t s had been a t t a c k ed . The e ffec t of th e bee tle on d if fu se knapweed was no t s t u d ie d in detail b ecau se of th e small s ize of th e popu ­ la t ions . However , th e bee tle te n d s to r e d u c e seed p ro du c t io n an d may p r e ­ v e n t r o s e t te s from bo l t in g . T h e re was also a indication t h a t th e beetle had a s y n e rg i s t i c e f fec t on s eed reduc t ion in p la n t s s t r e s s e d by d r o u g h t o r a t ta ck ed by th e s eedhead gall f l ies . Contro l S t r a te g y The seed red u c t io n ach ieved by th e biological con tro l a g e n t s a lready 146 e s ta b l i s h ed in B .C . shou ld have d e ­ c r e a s ed th e r a te of knapweed invasion from head la nd s on to tame p a s t u r e as well a s th e s p r e a d to new reg ions within w es te rn C anada . However , to r e d u c e knapweed with biological contro l a g e n t s to th e po in t w here th e chemical con tro l p rog ram s become u n n e c e s s a ry will r e q u i r e th e e s tab l i shm en t o f more b iocontro l a g e n t s on knapweed in C anada . C u r r e n t Research U n iv . o f B r i t i sh Columbia: Rob Powell, a g r a d u a t e s t u d e n t a t th e Univ . of B r i t ish Columbia, is c u r r e n t l y work ing on th e e f fec t o f th e bee t le , S ph enop te r a on d i f fu se knapweed . P re l im inary an a ly s is o f h is d a ta show th a t th e beetle has a s ign if ic an t e f fec t on bo th th e size of th e bo lted p lan ts and th e p ropo r t ion of good se edhead s p e r p lan t . fREQUENCY Of SHOOT WEIGHT CLASSES WITH AND WITHOUT SPIIENOPTERA Legend B K wm VMtwof rou M( SEYenTY UetenaYtET 2 TO 4G SJlOOT WClCUT For more information o r to be added to th e mailing list p lease con tac t : Ce les t ine Lacey P lant S Soil Science Dep t. Montana S ta te Un ive rs i ty Bozeman, MT 59717-0002 Macdonald Campus o f McGill Univ. D r. A. K. Watson r e p o r te d th a t c u r r e n t r e s e a rc h involves th e eva lua tion of r u s t fung i ( Puccinia s p p . ) as biocontro l a g e n t s of d i f fu se , s p o t te d and Russian knapweed and yellow s t a r th i s t l e . G radua te S tu d e n t P ro jec ts 0 . A nas . S tud ie s on th e mass c u l t u r ­ ing o f P a ranqu in a p ic r id is (nematode) and i ts h o s t / p a r a s i t e re la t ion sh ip with Russ ian k n ap ­ weed. M. Clement. Evaluat ion of Puccinia c e n ta u re a e (a r u s t ) fo r th e biolog­ ical con tro l o f s p o t te d knapweed . C . R efu se . B iosys tematics of N . America s p o t te d knapw eed . C. C ran ch . T h r e a t o f N. American safflower to poss ib le in t roduc t ion of knapweed r u s t s . Spo t ted Knapweed in E a s te rn Canada D r . Watson r e p o r te d t h a t app rox im a te ly 1700 ha (4165 a c . ) a re in fe s ted with s p o t te d knapweed in e a s t e rn Canada with major in fes tions o c c u r r in g in G r e y , H as t ing s , N orh tumber land and Simcoe coun tie s in O rna r io and in Iberv il le and Deux Montagnes coun tie s in Quebec . Spo tted knapweed has been r e p o r te d to o ccu r in New B runsw ick and in Nova Scotia , bu t is no t a weed problem in th e s e p ro v in ce s . A lbe r ta Shaffeck AM r e p o r te d t h a t spo t ted and d i f fu se knapweed was d is cove red in A lb e r t in 1974, and c u r r e n t l y in fes ts a b o u t 150 ha (375 a c . ) in th e s ou th e rn p a r t o f th e p ro v in ce . Environmenta l cond it ions a re ideal fo r knapweed g row th , and an e s t im a ted I million ha (2 .5 m a c . ) a re su s c ep t ib le to invas ion . T h u s , A lbe r ta has in i t ia ted an ac tive chemical p rog ram to e r a d ic a te the weed from th e p rov ince . Additional informa­ tion on th is p rog ram will be r e p o r te d on in th e following is sue . 147 % Knapweed Symposium The knapweed symposium held April 3 and 4 in G rea t Falls , MT was a g r e a t su cce s s with ove r 100 people a t t en d in g the p ro g ram . R e se a r c h e r s , r a n c h e r s , and ex ten s ion p e rsonne l r e p r e s e n t in g 7 s t a te s and p rov in ce s p r e s e n te d c u r r e n t r e s e a r c h p rog ram s and r e s e a rc h n eed s for knapweed con tro l . The s e s s ion s inc luded information on b io log ical , c u l tu r a l , and chemical con tro l o f sp o t te d and d i f fu se knapweed and yellow s t a r th i s t le . R anche rs and e x te n ­ sion p e rsonne l s t r e s s e d th e c u r r e n t p rob lems and r e s e a rc h n eed s conce rn ing sp o t te d and d i f fu se knapw eed . The p ro ceed in g s from th e s e s s ion s will be pub l i sh ed th i s summer. We app re c i a te th e s u p p o r t and encou rag em en t from all tho se who a t t e n d ­ ed th e symposium . A special th a n k s to John Lacey , Pete Fay , and Tim Chicoine fo r o rg an iz ing th e symposium . We also a p p re c ia te th e s u p p o r t o f th e Knapweed Action Committee, Montana Weed Contro l A ssoc ia t ion , Lewis and C la rk Conse rva t ion C is t , and Lincoln Coun ty Conse rva t ion D i s t . , Western Montana Weed counc il , and Dow Chemical Company. MONTANA NEWS Moving On Tim Chicoine r e c en t ly f in ished h is MS d e g r e e a t MSU and h a s ta k en a job with Dupon t Chemical Co. T im 's th e s is inc luded sp o t te d knapweed con tro l with chem icals , seed lo ngev i ty , and th e po ten t ia l m igration o f s po t ted knapweed in Montana. The r e s u l t s of h is r e s e a rc h will be pub l i sh ed in th e n ex t seve ra l i s su e s o f th i s n ew s le t te r . We will miss T im 's c o n t r ib u t io n s to o u r knapweed p rog ram in M on tana , however seve ra l of his s tu d ie s will be c o n t in u e d . Long - te rm Contro l Exper im en ts were e s tab l i sh ed a t two locations in Montana in 1979 by L a r ry B ake r . These e xpe r im en ts were u sed to de te rm ine th e du ra t io n o f contro l o f s po t ted knapweed with I Ib /A o f T o rd o n . Initial re invas ion o f p lo ts by sp o t te d knapweed began in 1982, 3 y e a r s following h e rb ic id e app l ic a t io n s . However , in 1983, contro l a t th e two locations remained a t 98 and 88%. T h e re was no in c re a se in con tro l when 2 ,4 -D amine was added to Tordon . Table I : S p o tte d Knapweed c o n tro l 50 months a f t e r h e rb ic id e a p p l i c a t io n a t II5 Ovando, Montana. Rate Date o f % C on tro l T reatm en t Ib/A T reatm en t Harlow ton Ovando 2 ,4 -D amine 2 + Tordon 1/4 5-21 -79 88 .0 98 .5 Tordon 1/4 5-21 -79 8 6 .0 100 .0 2 ,4 -D amine I 99 .0+ Tordon 1/4 5-21 -79 91 .0 2 ,4 -D amine 2 98 .0♦ Tordon 1/4 6 -13 -79 88 .0 C on tro l 0 0 .0 0.0 148 RurmGcR FBS I Knapweed E rad ication! Schafeek AM r e p o r te d th a t d if fu se and sp o t te d knapweed were f i r s t d is cov ­ e r e d in A lbe r ta in 1974. S ince then an in ten s iv e e rad ica t ion p rog ram has been in e f fec t to locate and d e s t r o y th e s e weeds . T h e re is app rox im a te ly 150 ha (375 a c re s ) c u r r e n t l y in fe s ted in A lb e r ta . T hese in f e s ta t io n s a r e la rge ly confined to t r a n sp o r t a t i o n rou te s and a d ja c en t r a n g e - land in th e s o u th e rn p a r t of the p ro ­ v in ce . Climate and soil cond it ions a re ideal fo r knapweed g row th in th i s p a r t of th e p rov in ce and an e s t imated one million h e c ta r e s (2 .5 million a c r e s ) a r e s u s c e p ­ tib le to invas ion . Both knapweeds a r e l is ted as r e ­ s t r i c t e d weeds in A lbe r ta u n d e r the Provincial Weed Contro l aC t . T h is means t h a t it is m anda to ry fo r th e landowner o r o c cupan t to d e s t ro y th e s e weeds if found on h is p r o p e r t y . Also, it is m anda to ry for weed in s p e c to r s to i s sue weed notices to landowners to d e s t r o y th e s e weeds . T h ro u g h th e coope ra t iv e e f fo r t of all local munic ipal it ies and s u p p o r t from the P rovincial G ove rnm en t , th e e rad ica t ion p rog ram is p ro g r e s s in g v e ry well. The in fes ta t ion on 150 h a . has been k ep t in check a nd is be ing r e d u c e d . While new in fe s ta t io n s have been fo und , many o f the or ig inal in fe s ta t io n s have been e ra d ic a te d . To rdon has p rov id ed th e b e s t con tro l fo r as long a s 3 y e a r s . However , in g rave l ly o r l ig h te r so i ls , con tro l is r e ­ du ced to I o r 2 y e a r s . S ince th e u se o f T o rdon is r e s t r i c te d in A lb e r ta , 2 ,4 -D and Banvel a r e common­ ly s u b s t i t u t e d for i t . However th e se h e rb ic id e s h ave no t been as e ffec t iv e . *NOTE* Because of th e s u cce s s of th is e f fo r t in A lb e r ta , North Dakota is a dop ­ t ing an e rad ica t ion p rog ram in the w es t­ e rn p a r t of th e s t a te whe re knapweed in f e s ta t io n s a r e j u s t be ing d is cove red . BRITISH COLUMBIA NEWS Program P rev en t s Knapweed T akeove r Roy C ran s ton r e p o r te d th a t a p ro t e c ­ tion p rog ram in i t ia ted in 1970 in th e E. Kootenai Region o f Canada has been e f fec ­ t ive in p r e v e n t in g knapweed tak eov e r of g r a s s l a n d s in th e Car ibou -Ch i Ico t in , Thompson-Nicola and E. Kootenai r e g io n s . The p rog ram has inc luded four main com­ ponen ts : * In ten s iv e Awarenes s E ffort: The aw a ren e s s p rog ram has inc luded n ew sp ap e r a d v e r t i s em en ts , radio and te le ­ vis ion p r e s e n ta t io n s , p roduc t ion o f a 16-mm film, a knapweed b ro c h u r e , bumper s t i c k ­ e r s , h ighway s i g n s , knapweed s ig n s on r a n g e a c ce ss ro a d s , knapweed a le r t s for h u n t e r s and f i s h e rm en , in fes ted hay w a rn ­ ing p o s t e r s , d i s t r ib u t io n of botan ica l m oun ts , mall and fa ir d i s p la y s , and semi­ n a r s with r ang e u s e r g r o u p s . * Equipment and Material Loan: Equipment, inc lud ing 10O gallon sk id mount s p r a y e r s , b a ckpack and micron Herbi s p r a y e r s , and a PTO -d r iv en boom s p r a y e r were made ava ilab le to r a n c h e r s a t no c o s t . Herbicidal samples fo r d em on s tra t io n s were d i s t r i b u te d with each s p r a y e r . * P rofess ional S e rv ic e s : G ran ts to s u p p o r t r e s e a rc h on b iocon­ t r o l , a l le lopa thy , and remote s en s ing were ava ilab le . * Weed Contro l g r a n t s were made availab le to regional d i s t r i c t s ($5,000 p lu s 50% of addit ional e x p e n d i t u r e to a maximum of $35,000 a n n u a l ly ) . G ra n ts fo r l ives tock assoc ia t ion s were ava i lab le . A maximum of $1 5,000 p e r a ssoc ia tion - u ti lized mainly for h e rb ic id e p u rc h a s e . Range land Herb ic ide S p ray e r L a r ry Thomas and Roy C ran s to n deve loped a m icro-max u l t ra - low volume s p r a y e r to be u sed for con tro l of knapweed on r a nge land . The s p r a y e r in c r e a s e s e ff ic iency of o th e r g ove rnm en t ag en cy knapweed contro l s p r a y u n i t s by d ec re a s in g 149 th e volume o u tp u t o f s p r a y e r s . Th is allows for more a c r e s to be t r e a te d p e r day th an with conven tiona l equ ipm en t . The s p r a y e r co n s i s t s o f th r e e Micro-Max U ltra-low sp inn ing d isc nozzles mounted on in d ep end en t booms. Each boom is co lla red a ro u n d a 3 .5" x 13" pipe in which the booms can move v e r t ica l ly in d ep end en t o f each o th e r . Th is sys tem is mounted to th e r e a r bumper o f the v eh ic le . The sys tem allows a four -whee l d r iv e p ickup with a s p r a y ta n k to cover re la t iv e ly r o u g h , open ra n g e a t 6 to 7 km /h , c o n tou r ing to the t e r r a i n , and g iv ing an e f fec t iv e s p r a y sw a th of 5 .4 m e te rs (17 f e e t ) . For add it iona l information con­ c e rn in g th is s p r a y e r , p lease con tac t Roy C ra n s to n , 162 Oriole R d . , Kamloops, BC Canada V2C 4N7. IDAHO NEWS Improvement o f S po tted Knapweed In fes ted P a s tu r e s S h e ly , C a l l ihan , and Huston of U n iv e rs i ty o f Idaho r e p o r te d th a t a s tu dy was in i t ia ted a t Hayden Lake, Idaho to de te rm ine th e long - te rm e f fe c t of Tordon and fe r t i l i z e r a lone o r in combination for r e s to ra t io n of s p o t te d knapweed in fes ted ra n g e la n d . To rdon a t .38 Ib/A and n i t rogen fe r t i l iz e r a t two r a t e s , 62.5 Ib/A and 125 Ib /A , were u s e d . T rea tm en ts were app lied in May and O c to b e r , 1982. In 1983, bo th the To rdon + 62.5 Ib/A n i t ro g en and Tordon + 125 Ib/A n i t rog en t r e a tm en ts in c r e a sed g r a s s y ie lds o v e r e i t h e r t r e a tm en t w ithou t Tordon o r To rdon w ithou t fe r t i l i z e r . T h e r e was no d i f f e ren ce in th e e f fec t of fe r t i l iz e r ra te upon g r a s s y ie ld s . The 62.5 Ib/A n i t rogen + To rdon t r e a tm en t app lied in the fall p roduced th e g r e a t e s t con tro l o f spo t ted knapweed and g r e a t e s t g r a s s y ie ld s . CALIFORNIA AND OREGON Court Ruling A real blow to knapweed contro l was no ted in a re c en t California co u r t ru l ing in a case b ro u g h t by SAVE OUR ECOSYSTEMS v e r s u s SECRETARY OF INTERIOR CLARK and SECRETARY OF AGRICULTURE BLOCK. In th e decis ion th e co u r t held t h a t th e programmatic Environmenta l Impact S ta temen ts which cove r all u ses within the s t a t e were u n accep tab le . In s tead th e c o u r t a sk ed th a t indiv idual Environmenta l Impact S ta tem en ts would have to be made for an y ac t ion s on federa l land involving th e u s e of 2 ,4 -D , S i lv ex , S imazine, A traz in e , D iruon , T o rd o n , D a lapon , Banve l, K ren i te , R oundup , and 2 -3 - 4 -T . The decis ion a sk ed th a t a wors t case a n a ly s is be p r e p a r e d for each he rb ic id e and each a rea to be s p r a y e d -! While th i s decis ion may be r ead to only app ly to California and O regon , it was th o u g h t th a t u n d o ub te d ly no fede ra l official will a t temp t to u se any o f th e d e s ­ c r ib ed h e rb ic id e s on an y federa l lands unti l th e decis ion is clarifiecT! * * * * * * * * For addit ional in formation o r to be a d d ed to th e mailing l i s t , p lease con tac t : C e les t ine Lacey Plant 6 Soil S c i . D ep t . Montana S ta te U n ive rs i ty Bozeman, MT 59717 150 PLANT & SOIL SCIENCE DEPARTMENT MONTANA STATE UNIVERSITY BOZEMAN. MONTANA 59717 VOLUME Il OCTOBER, 1984 ISSUE III * SUMMERTIME IN MONTANA! Eradica tion P rogram Pays Shafeek AM, v eg e ta t io n management sp ec ia l i s t , Edmonton, r e p o r te d th a t 1984 was a n o th e r su cces s fu l y e a r in the Knapweed Erad ica tion P rogram . All known in fe s ta t ion s were in sp ec ted and t r e a te d a s r e q u i r e d . S evera l s i tes a p p e a r to be e rad ic a ted as no p lan ts have been found for 2 o r 3 y e a r s . Such s i te s will be monitored to e n su r e th ey remain k n a pw eed - f r e e . T he pub lic aw a ren e s s campaign is con t inu ing and is p ay ing off . More landow ne rs , techn ica l sp e c ia l i s t s , and field s t a f f a r e s e a r c h in g for knapweed and all s i g h t in g s a r e r e p o r te d and ca ta ­ logued in a compu te r ized p rog ram . The su c c e s s o f th e aw a ren e ss campaign is obv ious b ecau se th e r e a r e fewer total a c r e s , how eve r , more known in fes ­ ta t ions have been r e co rd ed . Both B ri t i sh Columbia an d Montana h av e coope ra ted v e ry well in main ta in ­ ing a k n apw eed - f re e b u f f e r zone close to A lb e r ta ' s b o r d e r s . T h e i r e f fo r t s a r e g r e a t ly a p p re c i a te d . --— BRITISH COLUMBIA, CANADA Fall Applied H erb ic ides Roy C ra n s to n , weed spec ia l i s t , Kamloops, r e p o r te d on th e effec t o f fou r fall app lied h e rb ic id e s on d if fu se knapweed con tro l . T o r d o n , C lean , Dowco 290 (L o n t r e I ) , and Carlon were app lied on November 15, 1982 n e a r Kamloops, B .C . The t r e a tm en ts were r a te d for p e r c e n t con tro l o f d if fu se knapweed on March 18, 1983, A ugu s t 1 9, 1983, and S ep tem be r 10, 1984 (T ab le I ) . Fall app l ied Tordon and Dowco 290 p rov ided exce l len t con tro l of seed l ing and bo lted d i f fu se knapweed in th e y e a r following t r e a tm en t . Initial e a r ly s p r in g se tb a ck o f knapweed by Clean and Carlon was no t ev id en t in late summer. Tw en ty - tw o months following app l ic a t io n , To rdon was stil l p rov id ing exce l len t c o n t ro l . No bolted p lan t s were e v id en t in Dowco 290 plo ts a f t e r 22 mon ths , how eve r , numerous seed l in g s and ro s e t t e s were ap p e a r in g . No g r a s s in ju ry was no ted with any of th e h e rb ic id e s u s ed . T ab le I : E f f e c t o f fo u r f a l l a p p l ie d h e r b ic id e s on d i f f u s e knapweed c o n t r o l . T rea tm en t R ate a . l . / h a . ( I b . / a c ) 3 /1 8 /8 3 8 /1 9 /8 3 9 /1 0 /8 4 Tordon 22K 0 .5 6 kg ( 0 . 5 ) 5 5 .5 100 .0 9 5 .5 Tordon 22K 1 .1 2 kg ( 1 . 0 ) 1 0 0 .0 1 0 0 .0 1 0 0 .0 C lean 35 gr ( 0 .0 3 ) 2 2 .0 0 .0 0 . 0 C le a n 50 gr ( 0 .0 4 ) 3 3 .3 0 .0 0 . 0 Dowco 290 200 gr ( 0 . 2 ) 9 6 .6 1 0 0 .0 5 9 .0 Dowco 290 4 0 0 gr ( 0 . 4 ) 1 0 0 .0 1 0 0 .0 6 6 .6 C ar lon 400 gr ( 0 . 4 ) 4 1 .0 0 .0 0 . 0 C ar lo n 800 gr ( 0 . 7 ) 3 3 .0 0 .0 0 . 0 ch eck - - 0 . 0 0 .0 0 .0 151 Knapweed A ffec ts Soil Microbe Activ i ty A ll is te r Muir and Walter Majak, Kamloops R esea rch S ta t io n , conduc ted s tu d ie s in 1983 to d e te rm ine th e re la ­ t ion sh ip be tween th e p re s e n c e o f k n ap ­ weed , soil microbial a c t iv i t y , and e x t r a c ta b l e soil p h eno ls . Soil r e s ­ p ira tion was u sed to measu re th e level o f soil microbial a c t iv i t y . The r e s u l t s o f th e i r r e s e a rc h s u g g e s te d t h a t k n a p ­ weed was no t se c r e t in g la rg e q u an t i t i e s o f pheno ls in to th e roo t zone Of the p l a n t s . However , th ey d id find redu ced r e sp ira t io n levels from soil u n d e r knapweed in f e s ta t io n s . Th is s u g g e s t s t h a t knapweed does a l t e r the soil microbial a c t iv i ty and ch ange the ac t iv e decomposit ion o f soil o rg an ic m a t te r . T h is may a f fe c t th e g row th of o th e r p lan t s o r enh ance th e g row th of k n apw eed . (In fo rmation p r e s e n te d a t th e Knapweed Symposium , A pri l , 1989). In sec t for D iffuse Knapweed Joe M cCaff rey , Moscow, ID, r e p o r te d th a t th e b ee t le , Sphenop te ra ju g o s l a v ic a , was re lea sed in Idaho m 1981 on d i f fu se knapw eed . A second re lea se was made in 1984 in s o u th - c en t r a l Idaho. Both re lease s i te s will be ev a lu a ted in 1985 to de te rm ine the su c c e s s of th e in sec t for con tro ll ing d i f fu se kn apw eed . Work is also con­ t in u ing on th e deve lopment o f a pheno logy model fo r th e seed head flies y_. a f f in is and U_. q u a d r i f a c i a t a . New Bio Contro l A gen ts (Agape ta zoegana and Pe lochr is ta m edu l lana ) th a t a t t a c k spo t ted k n ap ­ weed , was made in w e s te rn Montana in 1 984. The moth la rv ae a t t a ck and damage th e roo ts o f small s po t ted knapweed ro s e t t e s . S tud ie s will be conduc te d in 1985 to de te rm ine level of o v e rw in te r in g s u c c e s s . Additional re lea se s o f the two moths a r e p lanned for 1985. The two moths were collected by th e Commonwealth In s t i t u te o f Bio­ logical Contro l (C IBC) o f Delemont, Sw itze r land , as p a r t o f a c o n t r a c t a r r a n g em en t be tween th e CIBC and Montana S ta te U n iv e r s i ty . A 3 -y e a r s c r e en in g p ro jec t of two to fou r add it ional p rom is ing n a tu ra l enemies o f s p o t te d knapweed was s t a r t e d by the CIBC in 1984. Fund ing fo r th e p ro jec t is comprised o f monies rece iv ed in a g r a n t th ro u g h th e Montana Dept, o f N atu ra l Res. and C on se rv a t io n , match ing fund s by th e p rov in ce o f B r i t i s h Columbia, and USDA-CSRS special g r a n t f u n d s . Emphasis will be on two promising roo t-m in ing weevils . Call Flies Estab l ish A su r v e y o f th e d is t r ib u t io n o f th e two fly spec ies U . a f f in is and U. q u a d r i f a s c i a ta . was completed in May 1 984. TTie s u r v e y showed U. q u a d - r i f a s c i a ta , th e fly which m igra ted from Canada into Montana, to be e s tab l i sh ed th r o u g h o u t th e knapw eed in fes ted a re a s o f w e s te rn Montana. As e x p e c t e d , th e h ig h e s t numbers o f U. q u ad r i fa sc ia ta w ere found in n o r thw e s t Montana, close to th e flies' orig in in B r i t i sh Columbia. U. q u ad r i fa sc ia ta was found to a lready F e more widely d i s p e r s e d th an U. a f f i n i s , th e fly which was d e l ibe ra te ly in t ro du ced into Montana d u r in g 1973- 1977. Large popu la t ions o f U aff in is were fo und , b u t on ly w ith in a 3 to 5 mile rad iu s o f th e o r ig ina l s i te . (Note: The fou r seed head gall fly co l lec t ion /- w o rk shop s have r e s u l t e d in th e r e d i s ­ t r ib u t io n o f an e s t im a ted 5 million flies a t o ve r 900 knapweed s i te s in Mon tana ) . Jim S to r y , Co rva l l is , MT, r ep o r ted th a t th e f i r s t re lease in th e United S ta te s o f two roo t-m in ing moths 152 Tordon Rate S tudy Exper im en ts were e s tab l i sh ed a t two locations in Montana in 1982 to de te rm ine the e f fec t o f low ra te s of To rdon and T o rd o n /2 ,4 -D combinations on contro l o f s p o t te d knapweed . To rdon a t . 125 (1 /8 ) Ib a . i . / a c . c on t in ­ ued to p rov id e 100% contro l o f matu re s p o t te d knapweed p lan t s 24 months following h e rb ic id e app lica t ion . Com­ b ina t ion s o f To rdon and 2 ,4 - 0 inc rea sed sp o t te d knapweed contro l o v e r Tordon a t r a t e s less th an 1/8 Ib/A dlone. G ra s s p roduc t ion was 247 to 770% g r e a t e r on To rdon o r T o rd o n /2 ,4 -D t r e a t e d p lo ts than on u n t r e a t e d plots (Tab le I ) . T ab le I : E f f e c t o f v a r io u s r a t e s o f T ordon and T o r d o n /2 ,4 -D c om b in a t io n s on s p o t t e d knapweed c o n t r o l 24 m onths a f t e r a p p l i c a t i o n . P e r c e n t C o n tr o l on 7 /8 4 H a r l o w t o w n ” O v a n d o Trea tm en t Rate ( I b . / a c ) 2 , 4 - 0 0 I b /a c 2 .4 -D .1 I b /a c 2 .4 - 0 2 .4 - 0 2 I b /a c Tordon 22K 0 .2 5 100 100 100 100 Tordon 22K 0 .2 2 100 100 100 100 Tordon 22K 0 .2 0 100 100 100 100 Tordon 22K 0 .1 8 7 5 100 100 100 100 Tordon 22K 0 .1 2 5 100 100 100 100 Tordon 22K 0 .0 9 7 5 96 98 98 100 Tordon 22K 0 .0 6 2 5 95 97 77 97 Tordon 22K 0 . 0 0 86 0 0 Cash fo r Knapweed? Chuck Egan and Wayne Pearson (S t i l lw a te r Co. Ex tension Agen t and Weed S u p e rv i s o r , re s p e c t iv e ly ) have found a su cce s s fu l way to s top the sp r e a d o f s p o t te d knapw eed . Th is p a s t summer th ey o ffe red a $5.00 boun ty for each new p a tch o f s p o t te d knapweed d i s c o v e r e d , and an addit ional $55.00 if th e p a tch was completely con tro l led . Anyone less th an 18 y e a r s old could p a r t ic ip a te in th e boun ty p rog ram . A ccord ing to C hu ck , th e p rog ram cost only $1,100 to implement, and has saved th e coun ty $4,000 to $5,000. "We've had more pub lic educa t ion with th is p rog ram th an with an y o th e r weed p rog ram we 've t r ie d so f a r , " said C huck . " I t really g e t s people involved and c o nce rn ed a b ou t con tro ll ing kn apw eed ." C ong ra tu la t ion s to Chuck and Wayne for th e i r h a rd work and d ed ica ­ tion to o u r weed con tro l e f fo r t . Anyone in t e r e s t e d in implementing a "b oun ty " p rog ram in th e i r c oun ty shou ld con tac t Chuck Egan , S ti llwater C oun ty A gen t , P .O . Box 807, Co lumbus , MT 59019. Yellow S ta r th i s t l e R eported Yellow s t a r th i s t l e ( C en tau re a so ls t i t i a l i s ) , a close re la t iv e of spo t ted k n a pw eed , was r e p o r te d a t two locations in Gallatin C oun ty th is summer. The weed c u r r e n t l y in f e s t s a bou t 3 million a c r e s of r ange land in Califo rn ia , Idaho, O regon , and Washing ton . A 1981 field s u r v e y in Idaho showed th a t yellow s t a r th i s t l e in fe s ted 185,000 acres and was invad ing new a re a s a t th e r a te of a b ou t 5,000 a c re s p e r y e a r . Yellow s t a r th i s t l e has th e potentia l to become a se r io u s problem in Montana. L andowners , c oun ty a g e n t s , and weed s u p e r v i s o r s must be a le r t fo r th is weed so we can keep it o u t o f ou r s t a te . A yellow s t a r th i s t l e b o un ty p rogram may be th e key to f ind ing and e rad ica t ing th i s weed. * * * * * * * * * * * * * * * * * For more information o r to be added to th e mailing list p lease con ta c t : Ce les t ine Lacey Plant £ Soil Science Dept. Montana S ta te Un ive rs i ty Bozeman, MT 59717-0002 * C a r t o o n c o u r t e s y o f B i g f o r k E ag le Ii 153 APPENDIX B TABLE 34. LIST OF HERBICIDE DEMONSTRATION PLOTS 154 E xpe rim en t Mo: 83001001 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a t io n : G a l l a t i n County (N o r th e a s t o f c i t y dump in Bozem an.) D a te : 5 /2 9 /8 3 — R e tre a te d w ith a e r i a l a p p l i c a t i o n o f dicam ba on 6 /8 3 . T r t . No. *H e rb ic id e R ate k g /h a I P ic lo ram 0 .5 6 2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 4 Dicamba 2 .2 4 5 2 .4 -D 2 .2 4 6 C on tro l 0 .0 0 *No r e t r e a tm e n t s a p p l i e d i n '1984. E xpe rim en t No: 83002002 T i t l e : L ea fy Spurge D em on s tra tio n P lo t L o c a tio n : P e tro le um County (Don Kimmel h e a d q u a r te r s on s t a t e la n d s e c t i o n . ) D a te : 6 /3 /8 3 * 6 /1 9 /8 4 Ranch, one m ile n o r th w e s t o f T r t . No. H e rb ic id e Rate k g /h a *1 P ic lo ram 0 .5 6 *2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 *4 Dicamba 2 .2 4 *5 2 ,4 -D 2 .2 4 6 C on tro l 0 .0 0 * R e tre a tm en t a p p l i e d to h a l f o f p l o t in 1984. 155 E xpe rim en t No: 83003003 T i t l e : Knapweed D em on s tra tio n P lo t L o c a t io n : F e rg u s County (On r a i l r o a d bed n o r th w e s t M ile M arker 2 . ) D a te : 6 /3 /8 3 o f C a r g i l l P l a n t by R ate T r t . No. ^H e rb ic id e k g /h a 1 2 ,4 - 0 + 2 .2 4 P ic lo ram 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 4 Dicamba 1 .1 2 5 2 ,4 - 0 2 .2 4 6 C on tro l 0 .0 0 *No r e t r e a tm e n t s in 1984 becau se o f p oo r l o c a t io n . E xp e rim en t No: 83004005 and 83004006 N o te : E xp e rim en t No. 83004005 i s e n c lo s e d w i th in a fen c ed a r e a . H e rb ic id e t r e a tm e n ts a r e th e same f o r b o th e x p e r im e n ts . T i t l e : S p o t te d Knapweed D em on s tra tio n P lo t L o c a tio n : S ilv e rb ow County ( F ee ly E x i t , s o u th o f B u t t e . ) D a te : 6 /6 /8 3 R ate T r t . No. ^H e rb ic id e k g /h a 1 2 ,4 -D + 2 .2 4 P ic lo ram 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 4 Dicamba 1 .1 2 5 2 ,4 -D 2 .2 4 6 C o n tro l 0 .0 0 *No Ret r e a tm e n ts in 1984» 156 E xp e rim en t No: 83004007 T i t l e : L ea fy Spurge D em on s tra tio n P lo t L o c a t io n :Pow e ll County ( B e ila n b e rg Road— tak e r a c e t r a c k e x i t , f i r s t ro ad to r i g h t , th en w es t p a s t o ld s c h o o l h o u s e .) D a te : 6 /1 7 /8 3 * 9 /1 4 /8 4 T r t . No. T r t . Date H e rb ic id e Rate k g /h a *1 6 /7 /8 3 P ic lo ram 0 .5 6 *2 6 /7 /8 3 P ic lo ram 1 .1 2 3 6 /7 /8 3 P ic lo ram 2 .2 4 *4 6 /7 /8 3 Dicamba 2 .24 5 6 /7 /8 3 2 ,4 -D 2 .2 4 6 6 /7 /8 3 C o n tro l 0 .00 7 7 /2 7 /8 3 P ic lo ram 1 .1 2 8 9 /1 5 /8 3 P ic lo ram 1 .1 2 *R e tre a tm e n t a p p l i e d to h a l f o f p l o t in 1984. E xp e rim en t No: 83005008 T i t l e : S p o t te d Knapweed D em on s tra tio n P lo t L o c a tio n : M u s s e ls h e l l County (B runo R odegh ie ro R anch ,R oundup .) D a te : 6 /9 /8 3 * 6 /6 /8 4 T r t . No. H e rb ic id e R ate k g /h a 1 2 ,4 -D + P ic lo ram 2 .2 4 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 *4 Dicamba 1 .1 2 *5 2 ,4 -D 2 .2 4 6 C o n tro l 0 .0 0 * R e tre a tm en t a p p l i e d to h a l f o f p l o t in 1984 157 E xpe rim en t No: 83006009 T i t l e : R u ss ian Knapweed D em on s tra tio n P lo t L o c a t io n : Rosebud County ( B i l l Tadsen Ranch; F o r s y t h . ) D a te : 6 /1 0 /8 3 s ix m ile s w est o f R ate T r t . No. *H e rb ic id e k g /h a 1 P ic lo ram 0 .5 6 2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 4 Dicamba 2 .2 4 5 2 ,4 -D 2 .2 4 6 C on tro l 0 .0 0 *No r e t r e a tm e n t a p p l i e d i n 1984. E xp e rim en t No: 83007010 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a tio n : C u s te r County ( P h i l l i p Flemming R an ch .) D a te : 6 /1 0 /8 3 6 /1 2 /8 4 T r t . No. H e rb ic id e R ate k g /h a *1 P ic lo ram 0 .5 6 *2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 *4 2 ,4 -D + 2 .2 4 P ic lo ram 0 .5 6 5 Dicamba 2 .2 4 6 2 ,4 -D 2 .2 4 7 C on tro l 0 .0 0 *R e tre a tm e n t a p p l ie d to h a l f o f p l o t i n 1984. 158 E xp e rim en t No: 83008011 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a tio n : F a l lo n County (Two m ile s n o r th w e s t o f G len Rugg Ranch Hdq. on w es t s id e o f r o a d . ) D a te : 6 /1 1 /8 3 * 6 /1 3 /8 4 T r t . No. H e rb ic id e R ate k g /h a *1 P ic lo ram 0 .5 6 *2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 *4 2 ,4 -D + 2 .2 4 P ic lo ram 0 .5 6 *5 Dicamba 2 .2 4 *6 2 ,4 -D 2 .2 4 7 C on tro l 0 .0 0 *R e tre a tm e n t a p p l i e d to Ih a l f o f p l o t i n 1984. E xpe rim en t No: 83009012 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a tio n : Dawson County ( Engle Ranch, s o u th o f G le n d iv e .) D a te : 6 /1 2 /8 3 * 6 /1 3 /8 4 P ic lo ram Ret r e a tm e n ts (0 .5 6 k g /h a ) a p p l i e d to 1 /2 plo* T r t . No. H e rb ic id e Rate k g /h a *1 P ic lo ram 0 .5 6 *2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 *4 2 ,4 -D + 2 .2 4 P ic lo ram 0 .5 6 *5 Dicamba 2 .2 4 *6 2 ,4 -D •2 .2 4 7 C on tro l 0 .0 0 159 E xpe rim en t No: 83010013 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a t io n : R ich la n d County (F iv e m ile s n o r th w e s t on C h a r l ie C reek Road— Don Palm er R an ch .) D a te : 6 /1 3 /8 3 * 6 /1 4 /8 4 T r t . No. H e rb ic id e R ate k g /h a *1 P ic lo ram 0 .5 6 *2 P ic lo ram 1 .1 2 3 P ic lo ram 1 .6 7 4 P ic lo ram 2 .2 4 *5 Dicamba 2 .2 4 *6 2 ,4 -D 2 .2 4 7 C on tro l 0 .0 0 *R e tre a tm e n t a p p l ie d to h a l f o f p l o t in 1984. E xp e rim en t No: 83011014 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a t io n : V a lle y County (Funk o f H in d s d a le . ) D a te : 6 /1 8 /8 3 * 6 /1 5 /8 4 Ranch— th i r t e e n m ile s n o r th T r t . No. H e rb ic id e Rate k g /h a *1 P ic lo ram 0 .5 6 *2 P ic lo ram 1 .1 2 J 3 P ic lo ram 2 .2 4 *4 Dicamba 2 .2 4 *5 2 ,4 -D 2 .2 4 6 C on tro l 0 .0 0 * R e tre a tm en t a p p l i e d to h a l f o f p l o t in P ic lo ram r e t r e a tm e n t s were a p p l i e d a t a 1984. i r a t e o f 0 .5 6 k g /h a . 160 E xpe rim en t No: 63012015 T i t l e : L ea fy Spurge D em on s tra tio n P lo t L o c a t io n : T oole D a te : 6 /1 6 /8 3 County ( Tomsheck Ranch— E leven m ile s E a s t o f K ev in .) T r t . No. ^H e rb ic id e R ate k g /h a 1 P ic lo ram 0 .2 8 2 P ic lo ram 0 .5 6 3 2 ,4 -D P ic lo ram 2 .2 4 0 .5 6 4 P ic lo ram 1 .1 2 5 P ic lo ram 2 .2 4 6 Dicamba 2 .2 4 7 2 ,4 -D 2 .2 4 8 C on tro l 0 .0 0 *No r e t r e a tm e n t s made in 1984. E xp e rim en t No: 83012016 T i t l e : R u ss ian Knapweed L o c a tio n : Toole County D a te : 6 /1 6 /8 3 D em on stra tio n P l o t (E a s t o f g o l f c o u rs e ; M arias R iv e r . ) T r t . No. *H e rb ic id e R ate k g /h a I P ic lo ram 0 .5 6 2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 4 Dicamba 2 .2 4 5 2 ,4 -D 2 .2 4 6 C on tro l 0 .0 0 *No r e t r e a tm e n t s made in 1984. 161 E xp e rim en t No: 83016017 T i t l e : S p o t te d Knapweed D em on s tra tio n P lo t L o c a t io n : M eagher County ( Bob Hanson Ranch) D a te : 6 /1 5 /8 3 T r t . No. *H eb ic id e R ate k g /h a I 2 ,4 -D + 2 .2 4 P ic lo ram 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 *4 Dicamba 1 .1 2 *5 2 ,4 -D 2 .2 4 6 C on tro l 0 .0 0 * R e tre a tm en t a p p l i e d on h a l f o f p l o t in 1984- E xp e riem en t No: 83013018 T i t l e : S p p tte d Knapweed D em on s tra tio n P lo t L o c a t io n : F la th e a d County ( 1 ,0 0 0 ' s o u th o f M arker 101— L a k e s id e .) D a te : 6 /1 7 /8 3 * 9 /2 4 /8 4 S p rin g C reek Road—M ile R ate T r t . No • H e rb ic id e k g /h a I 2 ,4 —D + 2 .2 4 P ic lo ram 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 *4 Dicamba 1 .1 2 *5 2 ,4 -D 2 .2 4 6 C on tro l 0 .0 0 * R e tre a tm e n t a p p l i e d on h a l f o f p l o t in 1984« 162 E xpe rim en t No: 83014019 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a tio n : C ascade County (G re a t F a l l s . ) D a te : 9 /1 5 /8 3 T r t . No. ^H e rb ic id e R ate k g /h a I P ic lo ram 0 .5 6 . 2 P ic lo ram 1 .1 2 3 P ic lo ram 2 .2 4 4 Dicamba 2 .2 4 5 2 ,4 -D 2 .2 4 6 C o n tro l 0 .0 0 *No r e t r e a tm e n t s made in 1984- E xpe rim en t No: 83015020 T i t l e : S p o t te d Knapweed D em on s tra tio n P lo t L o c a tio n : S an d e rs County (N o rth o f P l a i n s . ) D a te : 6 /8 3 N o te s : P l o t s d e s tro y e d in 4/84» ;. No. H e rb ic id e R ate k g /h a I 2 ,4 -D + 2 .2 4 P ic lo ram 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 4 Dicamba 1 .1 2 5 2 ,4 -D 2 .2 4 6 C o n tro l 0 .0 0 163 E xpe rim en t No: 64008001 T i t l e : L eafy Spurge D em on s tra tio n P lo t L o c a tio n : S w ee tg ra s s County (Tom Brownly Ranch) D a te : 6 /6 /8 4 T r t . No. H e rb ic id e R ate k g /h a I P ic lo ram 1 .6 8 2 P ic lo ram 1 .1 2 3 P ic lo ram 0 .5 6 4 Dicamba 3 .3 6 5 2 ,4 - 0 2 .2 4 6 C o n tro l 0 .0 0 E xp e rim en t No: 8470002 T i t l e : S p o tte d Knapweed D em on s tra tio n P l o t L o c a t io n : G a l l a t i n County (F ly in g D Ranch— D a te : 6 /1 8 /8 4 -S pan ish Fo rk e x i t . ) R ate T r t . No. H e rb ic id e k g /h a 1 2 ,4 - 0 + 2 .2 4 P ic lo ram 0 .1 4 2 P ic lo ram 0 .1 4 3 P ic lo ram 0 .2 8 4 Dicamba 1 .1 2 5 2 ,4 -0 2 .2 4 6 C o n tro l 0 .0 0 164 E xpe rim en t No: 84006003 T i t l e : H e rb ic id e T re a tm en t L o c a tio n : F e rg u s County P e te r s o n Ranch H dq .) R e p l i c a t i o n : Three D a te : 6 /7 /8 4 on Sheep G razed Spurge (On h i l l t o p , a b o u t one m ile s o u th o f R a te T r t . No. H e rb ic id e k g /h a I Dowco 290 1 .1 2 2 2 ,4 -D + 1 .1 2 P ic lo ram 0 .5 6 3 P ic lo ram 1 .1 2 4 P ic lo ram 1 .6 8 5 Dicamba 2 .2 4 6 2 ,4 -D 2 .2 4 7 C on tro l 0 .0 0 165 APPENDIX Q SURVEY QUESTIONNAIRE f 166 CAN WEED CONTROL PRACTICES SE IMPROVED IN MONTANA ? vtoncana State Uhiversity Plant and Soil Science Department Bozeman, Montana Li cooperation with Cooperative Extension Service Bozeman, Montana B U S I N E S S R E P L Y M A I L NO POSTAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES — Postage Will Be Paid By - FIRST CLASS Permit No. 69 Bozeman, MT 59715 Montana State University Department of Plant & Soil Science Bozeman, MT 59717 167 D ear Landow ner: Weeds a re co s tin g M on tanan 's a b ou t $100 million d o lla rs a nnua lly in lost p ro d u c tio n . A lthough new a d v an ce s h av e b een made in weed c o n tro l , s ev e ra l w eeds c o n tin u e to s p re a d so ra p id ly th a t th ey a re th re a te n in g th e farm and ran ch o p e ra t io n s in th e s ta te . We would like to deve lop a s ta tew id e weed con tro l p rog ram in M ontana. H ow ever, it is im po rtan t th a t we h ave a c cu ra te inform ation on th e weed con tro l p ra c t ic e s th a t you a re c u r r e n tly u s in g . Only th en will we be ab le to d e s ig n o u r p rog ram s to b e s t fit y o u r n e ed s . T h e re fo re , I would a p p re c ia te y o u r a s s is ta n c e in com­ p le tin g th is q u e s tio n n a ire on weed con tro l p r a c t ic e s . R e su lts from th is s u rv e y will be u sed to e s ta b lish weed p rog ram s a n d d ire c t e x te n s io n e f fo r ts in M ontana. Your a n sw e rs will a lso tell u s w here add itio n a l weed r e s e a rc h is n eed ed . We a re on ly sampling fou r c o un tie s in th e s ta te , th u s y o u r re sp o n se is c ritic a l to th e s u rv e y . You can be a s su r e d of complete c o n fid e n tia li ty , in no way will y o u r re sp o n se bo linked to y o u r name. P lease r e tu rn yo u r q u e s tio n n a ire as soon a s p o s­ s ib le . J u s t d ro p it in th e mail a f te r you h ave an sw e red th e q u e s t io n s , no stam p o r enve lope is r e q u ir e d . If you h ave any q u e s tio n s co n c e rn in g th e q u e s ­ t io n n a ire , p lease co n ta c t me, my num ber is 994-5078. T hank you fo r yo u r c o u r te sy and h e lp . S in c e re ly , C e le s tin e Lacey G radu a te R esea rch A s s is t . VEED SURVEY I. Whac Cype of opera cion do you have? (check one or cure) fam (mosc income fran sale of grain or agronomic crop) ranch (nose income tru.i sale of livescock) I Co 2.5 acres ocher (specify) ________________ 2. Do you or your spouse liave income ocher chan from che sale of fam or ranch produces? 3. Do you lease or own your land or boch? lease land ______ cwn land ______ boch 4. Please check che degree Co which each of che following weds are a problem on land you manage. a no don' c problem problem know spotLed knapweed ______ ______ leafy spurge ______ ______ Kussian knapweed ______ ______ _____ dalmacion toadflax ______ ______ Canada cliiscle _______ ochers (specify) 5. Please check che degree Co which you feel leafy spurge and spocced knapweed arc a problem in Muncana. serious sIighc don' c problem problem know leafy spurge _______ ______ _____ spocced knapweed ______ 6. Du you have spocced or diffuse knapwed on any land chac you manage? yes _____ (concimie Co 6a) no _____ (skin Co number 7, page 3) I f you answered no Co number 6 above, please go Co number 7 page 3! 168 Page 2 6a. How many acres of spotted or diffuse knapweed do you Iiave? (check one) under I acre _____ I to 3 acres _____ 3 to 30 acres 30 to 60 acres 60 to 100 acres _____ more than 100 acres _____ 6b. How many acres of spotted or diffuse knapweed have you Created in cite pasc 3 years? 0 acres _____ 1-5 acres 5-10 acres _____ 10-20 acres 20-50 acres _____ more than 50 acres _____ 6c. What method of treacnent did you use? (check one or more answers) Biological (insects) ______ Herbiciues ______ Which herbicide(s) do you use? Tordon ______ Banvel ______ 2,4-0 ______ ocher (specify) Mechanical (plow, disk, e tc .) ______ No CreaC xaiL method used ______ Otner treatment methods used (specify) Od. Is your kn.ipwced control program cost effective? (check one) yes ______ (skip to mmber 7) no ______ (continue below) (I f no) please check why your program is not cost effective. Herbicides too expensive ______ Application cost too high ______ Value of land too low ______ other (specify) Page J 7. Do you liavc leafy spurge on any land you manage? yes _____ (continue to 7a) no _____ (skip to number 8 page 4) I f you answered no to number 7 please skip to number 3 page 4! 7a. flow many acres of leafy spurge do you have? under I acre 1-5 acres 5-30 acres _____ 30-60 acres _____ 60-100 acres more than 100 acres _____ 7b. How many acres of leafy spurge have you treated in the past 3 years? (check one) 0 acres _____ 1-5 acres _____ 5-10 acres _____ 10-20 acres _____ 20-50 acres _____ to re than 50 acres _____ 7c. What treatment ctzthod do you use? (check one or more) Mechanical (plow, disk, e tc .) _____ Biological (insects) _____ Herbicides _____ Which herbicidc(s) do you use? Tordon _____ 2.4-D _____ Otlier (specify) !Jo treatment methods used _____ Other treatment methods used (specify) 7d. Is your spurge control program cost effective? yes ____ (skip to number 8) no ____ (continue below) (I f no) please check why your program is not cost effective. Herbicides too expensive ____ Application costs too high ____ Value of land too low ____ otiiers (specify) 169 Page 4 8. Please indicate which reasons you feel are mosC ihportanu for landowners not creating leafy spurge and spotted knapweed. Race the below responses from I (most iiiporcanc) to 4 (least important). Fear of herbicides ____ Lack of information on wed control ____ Lack of application equipment ____ Value of land coo low to ju s tify treatment ____ Others (specify) ______________________ ____ 9. which of the following sources has provided you with the arise information in the past 2 years? Please ra te responses from I (most important) to 7 (least important) popular magazine _____ newsletter _____ radio or television _____ neighbor _____ Montana State University _____ Cooperative Extension Service Agri-business (chemical caipany) __ Others (specify) ____________ _____ 10. Whac should the Cooperative Extension Service do to Help landowners with weed control? ( l i s t in order of importance) Page 5 12. .AXild you like to receive a sirmary of the resu lts of th is survey? yes ______ I i . VtoulJ you like additional information on certain problem weeds? yes ____ (S-'«.*cf r which weeds) _____________ no _______ 14. Please p rin t your name and address below i f you answered "yes" to e ither questions 12 or 13." THANK YOU FOR YOUR COOPERATION! Please drop th is questionnaire in the mail. Ito envelope or stamp is necessary. 1 11. What kind of weed research would you like to see conducted a t lbncana State Lhiversity? ( l i s t in order of importance) 170 APPENDIX D RESEARCH TABLES AND FIGURES Jf 171 T a b le 35,. A L i s t o f A l l S p e c i e s O b s e rv e d on S i t e One (O vando ) an d S i t e Two (H arlow tow n). L o c a tio n Common Name L a t in B inom ia l ^ A utho r ^ Ovando P e r e n n ia l G ra s se s W este rn w h e a tg ra s s Smooth b rom eg ra s s T im othy K entucky b lu e g r a s s Agropyron s m i t h i i Bromus in e rm is Phleum p r a te n s e Poa p r a t e n s i s Rydb. Leys. L. L. . P e r e n n ia l F o rb s , W este rn y a rrow A rro w le a f b a ls am ro o t S p o t te d knapweed S i lk y lu p in e A c h i l le a m i l le f o l iu m B a lsam o rh iz a s a g i t t a t a .C en tau rea m acu lo sa L up inu s s e r i c e u s L. (P u rsh )N u tt Lam. P u rsh Annual F o rb s C la sp in g pepperw eed S to n e se e d O w lc lo v e r L ep id ium p e r f o l ia tu m L ithosperm um sp . O r th o ca rp u s sp . L. H a rlow to n P e r e n n ia l G ra s se s W este rn w h e a tg ra s s B lue gram a Smooth b rom eg ra s s P r a i r i e J u n e g ra s s T im othy Canada b lu e g r a s s K entucky b lu e g r a s s Agropyron s m i t h i i B o u te lo u a g r a c i l i s Bromus in e rm is K o e le r ia c r i s t a t a Phleum p r a te n s e Poa com p ressa Poa p r a t e n s i s Rydb. (HBK)Lag. L. P e rs . L. L. L. Annual G ra s se s Downy c h e a tg r a s s Bromus te c to rum L. P e r e n n ia l F o rb s L o u is ia n n a s a g ew o rt S p o t te d Knapweed. C in q u e fo i l S l e n d e r f l r . S c u r f -p e a Golden pea A r tem is ia lu d o v ic ia n a C en tau re a m acu lo sa P o t e n t i l l a sp . P s o r a le a t e n u i f l o r a T h e rm op s is r h o m b i f o l ia N u tt. L. P u rsh N u tt. Annual F o rb s S to n e se ed C la sp in g pepperw eed L ithosperm um sp . L ep id ium p e r f o l ia tu m L. Sh rubs A rk an sas r o s e W este rn sn ow be rry Rosa a rk a n sa n a S ym pho rica rpo s o c c id e n t a i l s P o r te r Hook. ^ L a t i n b i n o m i a l s a n d a u t h o r s a r e l i s t e d a c c o r d in g to H i tc h c o c k a n d C ro n q u is t ( 1 9 7 3 ) . 172 T ab l e 3 6 . Mean m o n th ly p r e c i p i t a t i o n d a t a f o r H a r low to n a n d Ovando , Mon tana f rom Ju n e 1982 t o O c t o b e r 1 9 8 4 . 1 M on th ly P r e c i p i t a t i o n (cm) Annua l D a te L o c a t i o n J a n Feb Mar Apr May J n J l Aug S e p t O c t Nov Dec X 1982 H a r l ow to n 6 . 3 5 . 0 2 .1 6 . 6 2 . 9 0 . 7 1 . 3 4 9 . 3 Ovando 6 . 6 2 . 0 0 . 8 3 . 2 1 . 2 1 . 7 4 . 6 41 .1 1983 K a r l ow to n 0 . 9 0 . 2 1 . 2 1 . 9 3 . 0 8 . 8 4 . 2 4 -4 5 . 2 3 . 9 1 . 8 2 . 0 3 6 . 6 Ovando 3 . 2 3 . 5 1 .1 1 .1 4 . 4 4 . 3 5 . 9 2 . 6 3 . 5 1 . 8 1 . 9 3 . 8 3 8 . 8 1984 H a r l ow to n 0 . 3 0 . 5 1 .0 3 . 5 4 . 2 4 . 2 0 . 7 6 . 0 3 . 4 0 . 7 Ovando 1 . 8 0 . 8 2 . 0 4 . 5 4 . 3 7 . 2 0 . 6 5 . 6 1 . 6 3 . 2 - 1 H a r l ow to n i s l o c a t e d a p p r o x im a t e l y 15 m i l e s n o r t h o f s t u d y s i t e 2 a n d Ovando i s l o c a t e d a p p r o x im a t e l y 16 m i l e s s o u t h e a s t o f s t u d y s i t e 1. T a b l e 3 7 ■ Mean m o n th ly t e m p e r a t u r e s f o r H a r l cw to n and Ovando , Mon tana f rom June 1982 t o O c t o b e r 1 98 4 . Mean M on th ly T em p e r a t u r e (C) Annua l D a te L o c a t i o n J a n Feb Mar Apr May J n J l Aug S e p t O c t Nov Dec X 1982 H a r l ow to n 1 4 .7 1 8 .2 1 9 .2 1 2 .3 7 . 6 - 0 . 5 - 2 . 7 5 . 8 Ovando 1 4 . 3 1 5 . 7 1 6 .6 1 1 .2 5 . 4 - 3 . 8 - 8 . 2 2 . 5 1983 H a r l ow to n 0 . 8 1 . 4 2 . 7 4 . 8 1 0 .0 1 4 . 9 19 .1 2 1 .0 1 2 .0 8 . 6 1 . 2 - 1 2 . 4 7 . 0 Ovando —4•1 —1 . 6 2 . 4 2 . 4 9 . 2 1 3 .6 1 6 . 0 17 .1 8 .1 3 . 5 - 1 . 2 - 1 5 . 7 3 . 8 1984 H a r l ow to n - 0 . 4 1 . 5 1 . 6 5 . 6 1 1 .0 4 5 . 0 2 0 . 2 2 0 .7 1 0 .6 5 .1 Ovando - 5 . 1 - 2 . 0 1 . 4 3 . 6 7 . 5 1 1 . 7 1 5 . 3 1 6 .3 7 .1 1 . 9 ^H a r low to n i s l o c a t e d a p p r o x im a t e l y 15 m i l e s n o r t h o f s t u d y s i t e 1 a nd Ovando i s l o c a t e d a p p r o x im a t e l y 16 m i l e s s o u t h e a s t o f s t u d y s i t e 2 . 173 T ab le 38!. R e p r e s e n ta t iv e S o i l P r o f i l e f o r S i te I ( Ovando, MT). A11 — O to 10 cm, d a rk g r a y i s h brown (10YR 3 /3 ) sandy loam (58% san d , 31% s i l t , 14% c l a y ) , v e ry d a rk brown (10YR 2 /2 ) m o is t ; weak, f i n e g r a n u l a r s t r u c t u r e ; 5% g r a v e l ; many f i n e and m odera te c o a rs e r o o t s . A l2 — 10 to 25 cm, d a rk g r a y i s h brown (10YR 3 /3 ) v e ry g r a v e l ly sandy , loam (60% san d , 27% s i l t , 13% c l a y ) , v e ry d a rk brown (1OYR 2 /2 ) m o is t ; weak, f i n e g r a n u la r s t r u c t u r e ; 35% g r a v e l ; many f i n e and m odera te c o a r s e r o o t s . B — 25 to 56 cm, brown ( 7 .5 YR 4 /4 ) v e ry g r a v e l ly sandy loam (67% san d , 21% s i l t , 11% c l a y ) , d a rk brown (7.5YR 4 /4 ) m o is t; m od e ra te , medium, s u b a n g u la r b lo ck y s t r u c t u r e ; 50% g r a v e l , 20% c o b b le ; many f i n e r o o t s . C — 56 to 100 cm, . brown (7.5YR 4 /4 ) e x trem e ly g r a v e l ly sandy loam (76% san d , 11% s i l t , 13% c l a y ) , d a rk brown (7 .5 YR 4 /4 ) m o is t ; m a s s iv e ; 65% g r a v e l , 35% c o b b le ; many f in e r o o t s . T ab le 39;. R e p r e s e n ta t iv e S o i l P r o f i l e f o r S i t e 2 (H a r low to n ) . A — 0 to 7 .5 cm, brown (10YR 4 /3 ) g r a v e l ly loam (42% sand , 29% s i l t , 26% c la y ) d a rk brown ( I OYR 3 /3 ) m o is t; weak f in e g r a n u la r s t r u c t u r e ; 40% g r a v e l ; many f i n e and few c o a rs e r o o t s . Cl — 7 .5 to 25 cm, brown (10YR 5 /3 ) v e ry g r a v e l ly sandy loam (81% ' s a n d , 7% s i l t , 11% c la y ) d a rk brown (10YR 3 /3 ) m o is t ; m ass iv e ; 65% g r a v e l , 2% c o b b le ; many f i n e r o o t s . C2 — 25 -55 cm, brown (TQYR 5 /3 ) v e ry g r a v e l ly sandy loam (80% s a n d , Sffo s i l t , 11% c la y ) brown (10YR 4 /3 ) m o is t; m a s s iv e ; 68% g r a v e l , 5% . c o b b le ; many f i n e r o o t s . C3 — 55 to 100 cm, brown (10YR 5 /3 ) v e ry g r a v e l ly sandy loam (86% san d , 5% s i l t , 9% c l a y ) , brown (10YR 4 /3 ) m o is t ; m ass iv e ; 78% g r a v e l , 15% c o b b le ; many f i n e r o o t s . 174 T a b le 4 0 . D i v e r s i t y o f O th e r F o rb S p e c i e s 24 M on th s F o l lo w in g A p p l ic a t io n o f P ic lo ram a t S i t e One (O vando)J L a t in B in om ia l P ic lo ram Rate (k g /h a ) S p e c ie s 0.00 0.07 0.11 0 .14 0 .20 0.21 0 .25 0 .2 8 A c h e l l ia I a n u lo s a ^ X Lepid ium p e r f o l ia tu m X Lithosperm um sp . X X P o t e n t i l l a s p . X O rth o c a rp u s s p . X X X X X X X X ^ P ic lo ram was a p p l i e d ion June 16 and 17 , 1982. ^The l e t t e r X i n e a c h row d e n o t e s th e p r e s e n c e o f th e f o r b i n t h e p ic lo ram t r e a tm e n t . T a b le 41 . D i v e r s i t y o f O th e r F o rb S p e c ie s 24 M on th s F o l lo w in g A p p l ic a t io n s o f P ic lo ram a t S i t e Two (H a r low to n )J L a t in B inom ia l S p e c ie s 0 .0 0 P ic lo rm 0 .0 7 0 .11 R a te s 0 .1 4 0.21 0 .2 2 0 .2 5 0 .2 8 p A r tem is ia lu d o v ic ia n a X X X Lepid ium p e r f o l ia tu m X X X L ithosperm um sp . X X P o t e n t i l l a sp . X X P so ra le a t e n u i f l o r a T h e rm op s is r h o m b ifo l ia X X X X X X X X X ^ P ic lo ram was a p p l i e d on June 16 and 17» 1982. 2 The l e t t e r X i n e a ch row d e n o te s th e p re s e n c e o f th e f o rb w ith in th e p ic lo ram t r e a tm e n t . 175 T a b l e 42. Mean m o n th ly p r e c i p i t a t i o n d a t a f o r Bozeman and Townsend , Montana f rom J u n e 1982 t o O c t o b e r 1 9 8 4 . 1 M on th ly P r e c i p i t a t i o n (cm) Annua l D a te Loca t i o n J a n Feb Mar Apr May J n J l Aug S e p t O c t Nov Dec X 1982 Bozeman 9 . 0 3 . 8 2 . 0 6 . 8 3 .1 0 . 8 2 . 4 4 7 . 7 Townsend 3 . 9 2 . 6 4 . 3 3 . 6 1 . 5 0 . 4 1 . 2 2 5 . 9 1983 Bozeman 0 . 3 0 . 9 2 . 2 2 . 9 4 . 7 8 . 4 6 . 6 5 . 3 6 . 8 5 . 2 5 . 3 2 . 5 5 1 . 0 Townsend 0 . 2 0 .1 1 . 2 0 . 8 1 . 2 7 . 6 1 1 . 9 3 . 7 3 . 0 2 . 0 0 . 4 0 . 6 3 2 . 8 1984 Bozeman 0 . 8 1 . 6 3 . 8 4 .1 4 - 2 6 . 8 2 . 6 4 . 3 4 . 9 3 . 5 Townsend 0 . 2 0 . 3 1 .1 1 . 3 2 . 9 7 . 5 2 . 0 5 . 7 1 . 4 1 . 8 - 1Townsend c l i m a t i c d a t a was u s e d f o r t h e b u r i a l s i t e a t t h e B a le F o l k v o r d Farm s i n c e i t i s more r e p r e s e n t a t i v e o f t h e s t u d y s i t e t h a n c l i m a t i c d a t a f rom T h re e F o r k s . T a b l e 4 3 Mean m o n th ly t e m p e r a t u r e s f o r Bozeman a n d Townsend , O c t o b e r 1984 1 Montana f rom Ju n e 1982 t o Mean M on th ly T em p e r a t u r e (C) Annua l D a te L o c a t i o n J a n Feb Mar Apr May J n J l Aug S e p t O c t Nov Dec X 1982 Bozeman 1 3 .7 1 7 . 6 1 8 .7 1 1 .7 6 . 6 - 2 . 8 - 5 . 3 5 . 1 Townsend 14 .8 1 8 . 4 19 .1 12 .1 7 .1 - 0 . 1 - 4 - 4 5 . 9 1983 Bozeman - 0 . 2 0 . 6 3 .1 3 . 7 9 .1 1 3 . 9 1 7 .7 19 .5 1 1 .8 7 . 6 0 .1 - 1 3 . 2 6 . 2 Townsend - 0 . 1 0 .1 3 . 9 5 . 0 1 0 . 6 1 5 . 3 1 8 . 3 2 0 . 2 1 1 . 9 8 . 0 2 . 4 - 1 2 . 7 7 .1 1984 Bozeman - 3 . 0 - 1 . 1 1 . 9 5 . 0 1 0 .6 13 .1 1 8 .4 1 8 .9 1 0 .8 4 . 6 _ Townsend - 2 . 6 0 . 3 3 . 0 6 . 4 1 1 . 8 14 .2 1 9 . 2 1 9 . 6 1 0 . 7 4 . 9 - 1 Townsend c l i m a t i c d a t a was u s e d f o r t h e b u r i a l s i t e a t t h e D a le F o l k v o r d Farm s i n c e i t i s more r e p r e s e n t a t i v e o f t h e s t u d y s i t e t h a n c l i m a t i c d a t a f rom T h re e F o r k s . 176 T ab le 44 • Changes in th e S o i l R ese rv e o f S p o tte d Knapweed Seeds A f te r Seed P ro d u c tio n was S topped on 6 -20 -82 W ith V a riou s C u l tu r a l P r a c t i c e s a t H arlow ton . V iab le S p o t te d Knapweed Seeds p e r 0.5 m2 M o n th sA f te r S e e d P ro d u c t i o n w a s S to p p e d T re a tm e n t 0 10 15 22 28 Harrow^ 420a 140b 107b 54b 76b R o ll 670a 195b 238b 141b 118b Burn 594a 203b 201b 22b 97b Mow 648a 301ab 246b 173b 86b Spray 248a 92b 115b 140b 108b C o n tro l 523a 564a 1214a 520a 813a CV% 30 16 16 22 9 1 M eans i n t h e sam e c o lum n f o l l o w e d by th e sam e l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t . th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . T ab le 4 5 . Changes i n th e S o i l R ese rv e o f S p o tte d Knapweed Seeds A f te r S eed P r o d u c t i o n was S to p p e d on 6 - 2 0 -8 2 W ith V a r io u s C u l tu r a l P r a c t i c e s a t Ovando. V iab le S p o tte d Knapweed Seeds p e r 0.5 m2 Months A f te r Seed P ro d u c tio n was S topped T re a tm e n t 0 10 15 22 28 Harrow ^ 549a 41b 86b 107b 32b R o ll 463a 53b 64 b 86b 43b Burn 439a 96b 109b 43b 32b Mow 447a 22b 164b 86b 21b Sp ray 502a 96b 53 b 21b 42b C on tro l 603a 607a 635a 639a 488a CV% 16 14 14 12 5 M eans i n th e sam e co lum n f o l l o w e d by th e sam e l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . T ab le 4 6 . The C o n c e n t r a t i o n o f 2 ,4 -D ( e x p r e s s e d a s T o t a l DPM's) T h a t Was R e c o v e re d i n th e L e a f Wash and D i f f e r e n t P a r t s o f S p o t t e d K napw eed P l a n t s from H a r lo w to n (H) and Ovando (0 ) , M ontana, 1, 4 , 8 and 12 Days F o llow in g A p p l ic a t io n . T o ta l DPM1' s 2 A ssayed P o r t io n Days A f te r a p p l i c a t i o n 1 4 8 12 L ea f Wash ^ H 918700a 0 931700a H 950400a 0 940400a H 931900a 0 918600a H 851600a 0 889800a t r e a t e d l e a f 59870a 58750a 38310a 54480a 45520a 56640a 38460a 43430a le a v e s w ith t r e a t e d l e a f 9619a 3531a 10990a 12550a 9292a 7550a 9678a 16263a o th e r l e a v e s 3001a 2113a 4824a 5664a 6245a 3036a 6667a 2374a crown 3648a 5416a 12550a 10990a 13650a 11750a 25030a 5347a up p e r r o o t 3307a 3234a 6532a 9447a 12700a 16040a 17090a 8958a low er r o o t 512a 432a 1367a 2337a 3638a 4447a 5913a 4330a T o ta l 998657 1005176 1024973 1035822 1022945 1018063 954442 970502 Means in row s f o r e a ch d a te fo llo w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 5 p e r c e n t l e v e l u s in g th e LSD t e s t . t o t a l of 1 ,0 6 7 ,0 0 0 DPM's were a p p l ie d to e a ch p l a n t . 177 20 40 60 80 100 1 20 140 S p o t t e d K n a p w e e d L e a f Ma t e r i a l (mg ) 160 F ig u re 19 . O x id iz e r E f f i c ie n c y Curves f o r S p o tte d Knapweed Leaf M a te r i a l . 178 179 66 • O 40 80 120 160 200 240 S p o t t e d K n a p w e e d R o o t Ma t e r i a l (mg ) F ig u re 20 . O x id iz e r E f f i c ie n c y Curves f o r S p o tte d Knapweed Root M a te r ia l . 762 10382986 5