Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Wheat stem sawfly parasitism in varying field sizes and tillage systems in dryland wheat in Montana(Montana State University - Bozeman, College of Agriculture, 2001) Runyon, Justin BlakeItem Pathogenicity of Vairimorpha sp. (Nosematidae: Microsporida) in the Mormon cricket, Anabrus simplex (Tettigoniidae: Orthoptera)(Montana State University - Bozeman, College of Agriculture, 1991) Currey, David MichaelItem Aphelinus sp. nr. varipes (Hymenoptera: Aphelinidae) as a potential biological control agent of Russian wheat aphid Diuraphis noxia (Mordvilko) (Homoptera: Aphididae)(Montana State University - Bozeman, College of Agriculture, 1991) Lajeunesse, Sherry E.Item Vertical transmission of a dimorphic microsporidium (Microspora) in the Mormon cricket, Anabrus simplex (Orthoptera: Tettigoniidae)(Montana State University - Bozeman, College of Agriculture, 1993) Djibode, FrancoiseItem The biology of Tephromyiella Atlanis (Ald.), a parasite of nymphal and adult grasshoppers(Montana State University - Bozeman, College of Agriculture, 1951) Howitt, Angus J.Item Mass rearing of Bracon cephi (Gahan) and B. lissogaster Muesebeck parasitoids of wheat stem sawfly, Cephus cinctus Norton, and temperature-induced mortality in host immatures(Montana State University - Bozeman, College of Agriculture, 2006) Robert, Godshen Robert Pallipparambil; Chairperson, Graduate Committee: David K. Weaver.Bracon cephi (Gahan) and B. lissogaster Muesebeck are host specific larval parasitoids of the wheat stem sawfly, Cephus cinctus Norton. A reliable source of these parasitoids is needed for inoculative releases into sawfly infested wheat fields in Montana. Large walk-in field screen cages were used to confine sawflies and parasitoids on wheat. Factors affecting the successful establishment of sawflies in wheat and subsequent attack by parasitoids were tested. Treatments consisted of cage modifications such as windows for enhancing the amount of light, food sources for parasitoids, increased light plus food sources, and a control. Methods for delivering adult sawflies into the cages were also investigated. The mass rearing cages with the windows had significantly greater sawfly infestation and parasitism when compared to the cages without windows. The sawfly infestation was low the first year, while the percent parasitism was quite high, indicating that the major impediment to mass rearing was obtaining greater sawfly infestation. We obtained higher amounts of infestation and parasitism for the second year when the method of introduction of C. cinctus adults into the rearing cage was changed, and this difference was more obvious than any treatment effects.Item Impact of harvest operations on parasitism of the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae)(Montana State University - Bozeman, College of Agriculture, 2005) Meers, Scott Byron; Chairperson, Graduate Committee: Wendell L. Morrill.Wheat stem sawfly, Cephus cinctus, has been a long term pest management challenge for wheat producers in Alberta, Saskatchewan, North Dakota and Montana. Many studies have laid the groundwork for biological control of this pest. Two species of parasitoids, Bracon cephi and B. lissogaster, have been shown to effectively attack C. cinctus in wheat Triticum aestivum L. Their effectiveness as part of an integrated pest management plan, however, has been highly variable. A survey was conducted to assess the distribution of the two Bracon parasitoids. A two pronged approach was used to better understand parasitoid spatial dynamics and parasitoid promotion. First, intensive field sampling was performed to determine the overwintering location of parasitoid cocoons in wheat fields. Second, wheat stems were cut at varying lengths to stimulate harvest management techniques that producers could employ. B. cephi occurred at most locations where sawflies were an agricultural concern, although the level is sometimes very low. B. lissogaster was only found in wheat in Montana. The vast majority of overwintering cocoons (>80%) were consistently found in the bottom third of standing wheat stems when measured prior to harvest.