Theses and Dissertations at Montana State University (MSU)
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Item The effect of various soil amendments and preceding crops on seedling disease of sugar beets caused by Aphanomyces cochlioides Drechs(Montana State University - Bozeman, College of Agriculture, 1949) Bellingham, Roscoe C.Item The effect of potassium upon growth and certain mineral and carbohydrate contents of sugar beets(Montana State University - Bozeman, College of Agriculture, 1951) Doll, Eugene C.Item Optimizing a Bacillus sp. for biological control of sugar beet Cercospora leaf spot(Montana State University - Bozeman, College of Agriculture, 1999) Collins, Douglas ParkerItem The effects of crop residues on seedling disease of sugar beets caused by Aphanomyces cochlioides drechs(Montana State University - Bozeman, College of Agriculture, 1958) Lyda, Stuart D.Item Studies on chemotaxis of Aphanomyces cochlioides Drech. zoospores to sugar beet seedlings(Montana State University - Bozeman, College of Agriculture, 1966) Rai, Palthad VittalItem The effects of soil temperature and moisture and certain biological factors on the pathogenicity of Rhizoctonia solani Kuhn to sugar beet seedlings(Montana State University - Bozeman, College of Agriculture, 1952) Fenwick, Harry S.; Chairperson, Graduate Committee: M. M. AfanasievThe effect of temperature and moisture and of certain biological factors on the pathogenicity of several isolates of Rhizoctonia solani to sugar beet seedlings tbs studied. Pathogenicity of six isolates of Rhizoctonia solani obtained from seedling and matured sugar beets was established on sugar beet seedlings in the greenhouse. Four of the six isolates were selected for further study on the basis of their virulence and total per cent disease produced on the beets. Two of the isolates were obtained from beet seedlings, the other two were obtained from matured beets. The minimum temperature for growth of these isolates in culture was, found to be near 10° C. The optimum growth for these cultures was at 29° C, and the maximum was near 40° C. Rhizoctonia disease was produced at both temperatures used (15° and 25° C) and at all moisture levels (55, 70, and 85 per cent of the total moisture holding capacity). More disease occurred at 25° C than at 15° C. Moisture level of the soil appeared to have less effect on the incidence of the disease than did temperature. The total per cent disease was greater with isolates obtained from seedling beets, also the average weight per plant and the average length of tops were smaller with these isolates than with isolates from matured beets. A test of the effect of inoculum of varying ages on beet seedlings In different stages of growth revealed that beets are subject to attack by Rhizoctonia at any stage of growth and that the age of the beet is more important than the age of the inoculum in total incidence of disease. Antagonistic action was exhibited by Trichoderma lignorum toward Rhizoctonia in soil and culture tests. Penicillium notatum did not appear to have any effect on Rhizoctonia in soil or culture tests. Streptomyces griseus appeared to increase the pathogenicity of Rhizoctonia in soil tests, but no conclusive results could be obtained in culture tests.Item Systemic resistance induction by Bacillus mycoides isolate Bac J : the mode of action on Beta vulgaris (sugar beet)(Montana State University - Bozeman, College of Agriculture, 2003) Bargabus, Rebecca Lynn; Chairperson, Graduate Committee: John E. Sherwood.Bacillus mycoides isolate Bac J, a non-pathogenic, phyllosphere-inhabiting biological control agent, reduced Cercospora leaf spot of sugar beet by 60-80% in glasshouse experiments, even when spatially separated from the causal agent, Cercospora beticola Sacc. Disease control was attributed to the ability of the bacterium to induce systemic resistance in the host, which was demonstrated through classical induced resistance challenge assays. Additionally, in glasshouse and field experiments three pathogenesis-related proteins, chitinase, beta-glucanase and peroxidase, that are accepted molecular markers of systemic induced resistance, were increased by nearly 2-fold in distal, untreated sugar beet leaves following treatment with Bacillus mycoides isolate Bac J and acibenzolar-S-methyl, a chemical inducer of systemic resistance. The increased activity in all cases was a result of the production of unique isoforms of the enzymes not found in the water treated control. The Bacillus mycoides isolate Bac J-induced systemic defense response was preceded by a biphasic oxidative burst. The hydrogen peroxide production pattern was similar in timing, but not intensity to that elicited by avirulent bacterial pathogens of sugar beet, Erwinia carotovora pv. betavasculorum isolates 1 and 6. Although normally coupled with programmed cell death, the oxidative burst elicited by Bacillus mycoides isolate Bac J was independent of the hypersensitive response. Observations made during the oxidative burst experiments provided keys for understanding the signaling in Bacillus mycoides isolate Bac J-sugar beet interactions, including signal delivery not being reliant upon stomatal conductance and sugar beet receptor location being cytosolic or plasma membrane bound. Additionally, the biochemical and oxidative changes observed in sugar beet following Bacillus mycoides isolate Bac J treatment were consistent with changes seen in other Bacilli-sugar beet interactions in which systemic resistance was induced. These chemical consistencies provided a framework with which to establish a host response-based high throughput screen for the systematic identification of novel, putative Bacilli biological control agents, the first such method of its kind.Item Evaluation of intercropped sugar beets Beta vulgaris L. with emphasis on competition for light(Montana State University - Bozeman, College of Agriculture, 1971) Ozkan, MuammerItem Integrated management of Cercospora leaf spot on sugar beet(Montana State University - Bozeman, College of Agriculture, 2004) Larson, Ben James; Chairperson, Graduate Committee: Barry J. Jacobsen.Cercospora leaf spot (CLS), caused by Cercospora beticola, is the most important foliar disease of sugar beets in Montana. Losses in research plots ranging from 5-15 metric tons per hectare and 0.5-1.5% lower sugar in the last 7 years. Increased levels of storage rot, sugar impurities, and loss of sugar to molasses have also contributed to losses. Current management strategies are heavily dependent upon the application of a few registered fungicides. Continued use of these fungicides is threatened by registration removal through the Food Quality Protection Act of 1996, and the development of fungicide resistance in Cercospora beticola. This study examined management strategies for CLS integrating host-plant resistance, a CLS prediction model, registered fungicides, and a Bacillus mycoides biocontrol agent, BmJ. The effects of these strategies on disease development and yield were evaluated in field trials from 2001 to 2003. Disease levels were rated 4-5 times per season to generate a disease value for each treatment quantified as the area under the disease progress curve. Yield was determined as metric tons of beets and kilograms of extractable sucrose per hectare, and percent sucrose. Results showed more resistant varieties to give equal disease control with 1-2 fewer fungicide applications than more susceptible varieties without sacrificing yield in moderate to light CLS pressure. BmJ applications (4/year) reduced disease levels below the accepted economic threshold and gave disease control equal to fungicide applications when mixed with a single spray of a half rate of tetraconazole at disease onset. BmJ was highly effective in CLS management when combined with more resistant varieties. The levels of C. beticola fungicide resistance to benomyl, azoxystrobin and tetraconazole isolated from research plots in 2001 and 2002 were measured by spore germination and mycelial growth assays. Total insensitivity to benomyl was observed in more than 70% of isolates and reduced sensitivity to azoxystrobin and tetraconazole up to 10 ppm was also recorded. Preliminary results indicate growing more resistant varieties of sugar beet and spraying BmJ may aide in managing fungicide resistance by reducing the number of fungicide applications necessary for CLS control.Item Effects of mycofumigation using Muscodor albus and Muscodor roseus on diseases of sugar beet and chrysanthemum(Montana State University - Bozeman, College of Agriculture, 2004) Grimme, Eva; Chairperson, Graduate Committee: Barry J. Jacobsen.Methyl bromide-chloropicrin mixtures are the major chemicals used for soil disinfestation in the U.S. These chemicals are highly efficacious fumigants used for preplant soil fumigation in field and greenhouse production. They control soil-borne diseases, insects, nematodes and weeds. The 1996 International agreement to phase-out methyl bromide for soil fumigation will seriously reduce options for controlling soilborne pathogens. Mycofumigation is the use of antimicrobial volatiles produced by fungi such as Muscodor albus and Muscodor roseus for the control of other microorganisms. A synthetic mixture of organic components, which were originally identified in M. albus gases, provided disease control equal to the formulated fungus in terms of reducing damping-off by Aphanomyces cochlioides, Pythium ultimum, and Rhizoctonia solani. The effect of growth substrates for M. albus and M. roseus, their placement and fumigation period on efficacy for control of sugar beet seedling diseases was studied. Optimal growth substrates for M. albus were barley, canola, oat, and stabileze while optimal growth substrates for M. roseus were oat and barley. A 1-week mycofumigation period provided better control of damping-off than direct planting for both Muscodor sp. Mixing substrates with soil was superior to placement in the upper 25 % of the pot in Rhizoctonia-infested soil, whereas placement the in the upper 25 % of the pot was superior in Aphanomyces- and Pythium-infested soil. Field experiments indicate that mycofumigation of Aphanomyces-infested soil, buried 20 and 30 cm deep in field soil, increased seedling establishment of sugar beets. A winter survival study confirmed that M. albus does not survive the winter when buried (0 to 45 cm) in field soil in Montana. Storage of Muscodor sp. stabileze in a starch /sucrose / silica formulation was effective at - 10 °C and 3 to 5 °C for 5 months. In chrysanthemum experiments mycofumigation with M. albus and M. roseus resulted in significantly decreased Verticillium stem colonization compared to the V. dahliae pathogen control.