Scholarly Work - Research Centers
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Item Evaluation of the effectiveness of entomopathogens for the management of wireworms (Coleoptera: Elateridae) on spring wheat(2014-07) Reddy, Gadi V. P.; Tangtrakulwanich, Khanobporn; Wu, Shaohui; Miller, John H.; Ophus, Victoria L.; Prewett, Julie; Jaronski, Stefan T.Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), are serious soil dwelling pests of small grains, corn, sugar beets, and potatoes. Limonius californicus and Hypnoidus bicolor are the predominant wireworm species infesting wheat in Montana, particularly in the ‘Golden Triangle’ area of north-central Montana. Wireworm populations in field crops are increasing, but currently available insecticides provide only partial control, and no alternative management tools exist. In our study, three entomopathogenic fungi were tested for their efficacy against wireworms in spring wheat at two field locations (Ledger and Conrad, Montana, USA) in 2013. The three fungi (Metarhizium brunneum F52, Beauveria bassiana GHA, and Metarhizium robertsii DWR 346) were evaluated as seed-coat, in-furrow granular, and soil band-over-row drench applications in addition to imidacloprid (Gaucho® 600) seed treatment (as a chemical check), the approach currently being used by growers. Wireworm damage in these treatments was evaluated as standing plant counts, wireworm population surveys, and yield. The three fungi, applied as formulated granules or soil drenches, and the imidacloprid seed treatment all resulted in significantly higher plant stand counts and yields at both locations than the fungus-coated seed treatments or the untreated control. Significant differences were detected among the application methods but not among the species of fungi within each application method. All three fungi, when applied as granules in furrow or as soil drenches, were more effective than when used as seed-coating treatments for wireworm control, and provided an efficacy comparable or superior to imidacloprid. The fungi used in this study provided significant plant and yield protection under moderate wireworm pressure, supporting their value in the management of this pest.Item Developing nominal threshold levels for Phyllotreta cruciferae (Coleoptera: Chrysomelidae) damage on canola in Montana, USA(2014-12) Tangtrakulwanich, Khanobporn; Reddy, Gadi V. P.; Wu, Shaohui; Miller, John H.; Ophus, Victoria L.; Prewett, JulieThe flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae) are serious pests infesting canola (Brassica napus L.; Brassicales: Brassicaceae) in the Northern Great Plains of the United States. In Montana, P. cruciferae is the only flea beetle species that attacks canola during the crop growing stage. Management of P. cruciferae is usually focused on treating adults feeding on canola seedlings, which is the stage most vulnerable to flea beetle damage. In the Golden Triangle area in Montana, canola growers traditionally use seed treatments or calendar based spraying to control P. cruciferae. Here, we compared calendar-based spraying with seed treatment and threshold-based treatment. The experiment treatments included threshold levels (15–20, 25, 45% of leaf area damaged), calendar based sprays (15, 30 and 45 day intervals after plant emergence), seed treatments (imidacloprid), and untreated controls. The trials were done at two locations (Conrad and Western Triangle Agricultural Research Center). We found that calendar-based spraying at a 15-day interval did not differ significantly in yields from threshold-based treatment at 15–20% leaf damage. Also, the seed treatment did not give significantly higher yields compared to calendar-based sprays. A negative correlation was detected between leaf damage and yield in each treatment. Overall, calendar-based and threshold-based treatments were most effective in improving yields. However, treatment made at the threshold of 15–20% leaf area damage is recommended in order to reduce the number of chemical applications and also to reduce the possibility of selecting for resistance in flea beetles.Item Laboratory Host Range Assessment of a Predatory Pentatomid, Podisus maculiventris(Hemiptera: Pentatomidae) for Field Release on Guam(2011-12) Reddy, Gadi V. P.; Kikuchi, R.Predation by Podisus maculiventris (Say) (Hemiptera: Pentatomidae) was evaluated with Erionota thrax (L.) (Lepidoptera: Hesperidae), Pericyma cruegeri (Butler) (Lepidoptera: Noctuidae), Pareuchaetes pseudoinsulata Rego Barros (Lepidoptera: Arctiidae), Papilio polytes (L.) (Lepidoptera: Papilionidae) and Eudocima phalonia (L.) comb. nov. (Lepidoptera: Noctuidae). Both free-choice and no-choice experiments indicated that the P. maculiventris attacked and consumed all the larvae of the 5 species included in the tests. Although the larvae died at different intervals, most of them were dead within 24–120 h of the introduction of the predatory species. Since the P. maculiventris is polyphagous in nature and the present findings indicate that these predators will feed on the introduced biocontrol moth, P. pseudoinsulata, it is recommended not to take the predators out of the quarantine laboratory for the field release on Guam. Additionally, P. maculiventris will feed on some native species as they become available.Item Bioactivity of Selected Eco-Friendly Pesticides Against Cylas formicarius (Coleoptera:Brentidae)(2012-12) Leng, P. H.; Reddy, Gadi V. P.Seven low risk pesticides including 1.2% azadirachtin (Azadirachta indica), extracts from Morinda citrifolia, petroleum oil 97%, Beauveria bassiana strain GHA, mixed essential oils (rosemary oil: 0.25%, peppermint oil: 0.25%, thyme oil: 0.25%, clove oil: 0.25% and other ingredients: 99.00%), spinosad and malathion, were evaluated against adults of the sweetpotato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae) to determine potential insecticidal, repellent and feeding deterrence effects. Among the pesticides tested, A. indica and spinosad showed high insecticidal, repellent and feeding deterrence activity against C. formicarius. Spinosad, A. indica and malathion showed significantly higher insecticidal activity against C. formicarius. Similarly, these pesticides showed high repellency activity against adults, particularly 3–4 h after the treatment. The lowest food consumption was observed with the A. indica (0.8 g/adult/192 h), and the highest (9.9 g/adult/192 h) was with the petroleum oil spray. The other tested pesticides showed comparable activities. The chemicals we tested—particularly neem and spinosad—are therefore promising candidates as ecofriendly chemicals that could potentially replace broad-spectrum synthetic neurotoxins for control of C. formicarius.Item Action Threshold Treatment Regimens for Red Spider Mite (Acari: Tetranychidae) and Tomato Fruitworm (Lepidoptera: Noctuidae) on Tomato(2013-09) Reddy, Gadi V. P.; Tangtrakulwanich, KhanobpornThe tomato fruitworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is the foremost pest of tomato in the Mariana Islands. Similarly, the red spider mite, Tetranychus marianae McGregor (Acari: Tetranychidae), is a chief pest of vegetables particularly on tomato, Solanum lycopersicum L. (Solanaceae). However, the infestations by T. marianae are heavy during the early stages of crop growth, while infestations of H. armigera become prominent at later stages. Because no threshold levels are available for these pests, many growers apply up to 15 chemical applications per tomato cropping period. To reduce the regular spray schedules chemical applications and to prevent damage to foliage and fruit quality, the present study was undertaken for the development of action threshold levels for the timing of chemical applications for T. marianae and H. armigera on tomato in the Mariana Islands. Therefore, different threshold levels were evaluated for timing applications of Sun-spray 6E® horticultural oil against T. marianae and Aza-Direct®, neem against H. armigera on tomato in the wet and dry seasons at 2 locations, Dededo and Inaranjan, in Guam, USA during 2011 and 2012. Based on T. marianae infested leaves, incidence of T. marianae and yield levels, the plots sprayed at 8–12 mites/leaf in the dry season and 8–14 mites/leaf during the wet season had significantly lower leaf damage and T. marianae densities compared to a greater number of mites/leaf, regular based sprays and control plots. Likewise, an initial spray scheduled when 2 eggs of H. armigera were detected on 10 of the samples, followed by an added spray only if 2 damaged fruit or H. armigera larvae were detected per 50 immature fruit resulted in lower percent fruit damage and higher marketable yield compared to other threshold levels or a regular spray schedule.Item Registration of ‘Egan’ Wheat with Resistance to Orange Wheat Blossom Midge(2014-08) Blake, Nancy K.; Stougaard, Robert N.; Bohannon, B.; Weaver, David K.; Heo, Hwa-Young; Lamb, Peggy F.; Nash, Deanna L.; Wichman, David M.; Kephart, Ken D.; Miller, John H.; Eckhoff, Joyce L.; Grey, William E.; Reddy, Gadi V. P.; Lanning, Susan P.; Sherman, Jamie D.; Talbert, Luther E.Egan' hard red spring wheat (Triticum aestivum L.) (Reg. No. 1102, PI 671855) was developed by the Montana Agricultural Experiment Station and released in 2014. Egan is intended for production in areas of Montana infested with the orange wheat blossom midge (OWBM) (Sitodiplosis mosellana Géhin). Egan is resistant to OWBM due to antibiosis conferred by resistance gene Sm1. Egan also contains a chromosome segment originally introgressed into wheat from T. turgidum ssp. dicoccoides containing a gene for high protein (Gpc-B1) and a gene for stripe rust (caused by Puccinia striiformis Westend. f. sp. tritici) resistance (Yr36). Egan has shown high yield potential and high grain protein in nurseries grown under OWBM pressure in the Flathead Valley of Montana. Egan is the first hard red spring wheat cultivar with resistance to OWBM developed for Montana.Item Field Evaluation of Petroleum Spray Oil and Carbaryl Against Tetranychus marianae (Acari: Tetranichidae) on Eggplant(2014-03) Reddy, Gadi V. P.; Miller, R. H.Tetranychus marianae McGregor (Acari: Tetranychidae) is a pest of several perennial crops and is widespread in the Pacific Basin, including the Mariana Islands where it was first reported. The mite is also present in the West Indies, Bahamas, southern USA, Nicaragua, Argentina, Brazil and Southeast Asia. Eggplant growers apply carbaryl 10 to 15 times against this pest during each cropping period. Some growers no longer cultivate eggplant and tomato because of uncontrollable mite infestations. Previous indoor studies have shown petroleum spray oil (PSO) to be effective against T. marianae. We therefore examined the comparative effectiveness of PSO (Sun-spray 6E®) at the rate of 5mL/liter, and carbaryl at the rate of 1.5 mL/liter, against T. marianae on eggplant at 2 locations in Guam. The mean percentages of mite infested leaves and the population densities of T. marianae at both the locations were significantly higher in control plots than in treatment plots. PSO treatments with 6 and 15 sprays more effectively reduced the number of T. marianae-infested leaves and populations of T. marianae than carbaryl treatments. Marketable yields of eggplant from PSO treated plots were significantly higher than from the other plots. We recommend 6 applications of PSO at 15, 25, 35, 45, 55 and 65 days of after transplanting for managing T. marianae on eggplant.Item Evaluation of Spring Cereal Grain Yield to Over-Seeding on Soil Injected with Tractor Exhaust (2010)(Central Agricultural Research Center, 2010) Dahlhausen, S.J.; Wichman, David M.This report evaluates whether if injecting diesel tractor exhaust in to the soil, along with wheat seed would enhance grain yield. This trial was set up on both winter wheat and spring wheat. A farm scale exhaust injection system was used to establish wheat adjacent passes in fields of winter wheat and spring wheat. The first seeding pass was done without injecting the exhaust. The idea was to not have any fresh exhaust residues in the system when seeding the untreated check pass. The second pass was made with the exhaust injector system in operation. No start up fertilizer was placed with the seed. The moisture from the exhaust causes the granular fertilizer pearls to gum and build up on the opener. Therefore no starter fertilizer (NPK or S) was placed with the seed. Liquid N was applied sequential applications of 4 gallons per acre of 28-0-0 (11.2 lbs N)and 5 gallons of 24-0-0-0 ( 12.0 lbs N). This initial evaluation of injecting diesel exhaust into the soil along side the seed did not result in any positive results.Item Evaluation of Agronomic Performance of Winter Wheat, Spring Wheat, and Barley Cultivars in Recrop Near Moccasin, Denton, and Geraldine, Montana (2010)(Central Agricultural Research Center, 2010) Bates, S.R.; Berg, Jim E.; Blake, Tom; Bruckner, Phil L.; Dahlhausen, S.J.; Lanning, Susan P.; Talbert, Luther E.; Wichman, David M.; Vavrovsky, JoeThis report evaluates the performance of winter and spring cereal grain varieties in continuous crop and re-crop environments near Moccasin, Denton, and Geraldine. The 2010 central Montana continuous crop cereal grain yields were generally above average do to more plentiful precipitation distributed more evenly across the growing season. In some cases, winter wheat and spring crop yields were limited by weather caused by delays in seeding date. Late seeded winter wheat experienced early and mid-spring stand losses due to weak seedlings being exposed driving winds and some soil movement around the plant crowns. Sawfly was not as great of a factor in the winter wheat, except for some late seeded stands. While sawfly was a significant factor in spring wheat, the cutting generally was not as great as that experienced in 2009. Sawfly was less of a factor in the 2010 barley crop, also. 2010 was a somewhat stressful year, for the crop producer, due to the multitude of atypical weather events that occurred across the crop year starting with extreme cold and wet conditions in October 2009. While not all cereal crops were successful, those crops that had good stands generally produced good to outstanding yields. Sawfly cutting was sufficient to provide a good evaluation of spring wheat varieties and late seeded winter wheat varieties for tolerance, yet were not so severe as to wipe out any chance for useable yield data.Item Off-Station Winter Wheat Cultivar Performance on Fallow in Central Montana (2010)(Central Agricultural Research Center, 2010) Berg, Jim E.; Bruckner, Phil L.; Dahlhausen, S.J.; Vavrovsky, Joe; Wichman, David M.This report evaluates the relative performance of winter wheat cultivars and development lines in central Montana crop environments. The 2010 growing season conditions were generally optimal for wheat production. However, fall seeding conditions were challenging if the seeding was not accomplished prior to early October. For many locations, a combination of events led to early to mid-November seeding of winter wheat. Late seeding coupled with late April cold driving winds caused some marginal winter wheat stands. Generally, plentiful growing season precipitation helped off-set some of the stand deficiencies. Winter wheat continues to produce much higher yields than spring wheat at the Geraldine location. There is not a spring wheat trial established at Winifred due to 1990 trials which showed large yield differences between the spring wheat and winter wheat. Thus, the choice was made to discontinue spring wheat trials at Winifred. Winter wheat will continue to be the crop of choice in these areas.