Theses and Dissertations at Montana State University (MSU)
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Item Cephalosporium stripe of winter wheat: disease processes and effects(Montana State University - Bozeman, College of Agriculture, 1967) Pool, Robert Alfred FrankItem Etiology of Cephalosporium stripe in relation to the expression of resistance in cultivars of winter wheat (Triticum aestivum L.)(Montana State University - Bozeman, College of Agriculture, 1979) Morton, Joseph BrianItem The effect of Cephalosporium gramineum on yield components of various winter wheat genotypes(Montana State University - Bozeman, College of Agriculture, 1972) Johnston, Robert HowardItem Mycofumigation with Muscodor albus : effects on Verticillium wilt and black dot root rot of potato, effects on Glomus intraradices and ectomycorrhizal fungi, and M. albus proliferation in soil(Montana State University - Bozeman, College of Agriculture, 2008) Grimme, Eva; Chairperson, Graduate Committee: Barry J. Jacobsen.Muscodor albus Worapong, Strobel & Hess, isolate CZ-620 (MA) is an endophytic fungus that produces volatile organic compounds (VOCs) and non-volatile antimicrobial compounds. The use of these VOCs to inhibit or kill a wide range of microorganisms is termed mycofumigation. This dissertation focuses on parameters of MA mycofumigation including: production and bioactivity of previously un-described water-soluble antimicrobial compounds produced by MA; distribution of antimicrobial compounds from a MA point source in three soil types as measured by effects on Verticillium dahliae and Colletotrichum coccodes; control of V. dahliae and C. coccodes on potato; the ability of MA to colonize soil; and the effects of mycofumigation on ectomycorrhizal fungi (EMF) in vitro and on the colonization of onion roots by the arbuscular mycorrhizal (AM) fungus Glomus intraradices. The bioactivity of water-soluble compounds produced in potato dextrose broth was significantly increased as measured in growth reduction of C. coccodes, V. dahliae, and Rhizoctonia solani. No reduction was observed for Aphanomyces cochlioides and Pythium ultimum. Antimicrobial compounds from a MA colonized barley point source reduced V. dahliae and C. coccodes populations in soils by 60-100% at distances up to 9 cm from the inoculation source depending on soil type. Mortality rate ranging from 70-100% was observed within a 3 cm radius from the inoculation source. In both field and greenhouse trials, MA colonized barley formulation reduced Verticillium wilt and black dot root rot severity and reduced populations of both pathogens in potato tissue as measured by real-time quantitative PCR and serial dilution. Planting directly into mycofumigated soil previously infested with V. dahliae or C. coccodes resulted in equal control of the pathogens when compared to a one-week mycofumigation period prior to planting. After six weeks of incubation MA did not colonize sterile soil further than 0.5 cm away from a MA inoculation point. In vitro experiments showed that most of the tested EMF were inhibited in the presence of MA VOCs, but were able to resume growth when removed from VOCs. Incorporating MA into soil had no negative but supportive effect on onion root colonization by the AM fungus G. intraradices.Item Bacterial wilt management : a prerequisite for a potato seed certification program in Mali(Montana State University - Bozeman, College of Agriculture, 2007) Thera, Aissata Traore; Chairperson, Graduate Committee: Barry J. Jacobsen; Florence Dunkel (co-chair)Potato is one of the most important cash crops in Mali and has been well adapted to the Malian cropping systems and food habit. Bacterial wilt caused by Ralstonia solanacearum (Smith) Yabuuchi et al., (1995) has become a major problem causing important damage in production. The Race and biovar of the bacterium present in Mali were not known at the start of this thesis research and the objective of this research was to identify the race/biovar and to evaluate integrated control methods with the aim to produce high quality disease free seed potato in Mali. We have initially identified the biovar and Race of R. solanacearum affecting potato in Mali as Race 1 biovar 3. ELISA tests were used on soil and water samples to detect the presence of R. solanacearum. Three detections methods of the bacteria (bacterial streaming test, Agdia immunostrip test and Tetrazolium chloride media) in plant samples were compared; weeds and crops hosting the bacteria as sources of inoculums were identified using Agdia immunostrip test.