Theses and Dissertations at Montana State University (MSU)
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Item Genetic basis of wheat resistance to the wheat stem sawfly(Montana State University - Bozeman, College of Agriculture, 2016) Varella, Andrea Correa; Chairperson, Graduate Committee: Luther E. Talbert; Luther E. Talbert, Robert K. D. Peterson, Jamie D. Sherman, Nancy K. Blake, Megan L. Hofland, John M. Martin and David K. Weaver were co-authors of the article, 'Host plant quantitative trait loci affect specific behavioral sequences in oviposition by a stem-mining insect' submitted to the journal 'BMC plant biology' which is contained within this thesis. [SUBMITTED]; Megan L. Hofland, Micaela Buteler, Luther E. Talbert, Jamie D. Sherman, Nancy K. Blake, Hwa-Young Heo, John M. Martin and David K. Weaver were co-authors of the article, 'Temporal patterns of pith expression and retraction in wheat stems and its effect on resistance to the wheat stem sawfly' submitted to the journal ' ' which is contained within this thesis. [SUBMITTED] [NO MAG]; David K. Weaver, Jamie D. Sherman, Nancy K. Blake, Hwa-Young Heo, Jay Kalous, Shiaoman Chao, Megan L. Hofland, John M. Martin, Kenneth D. Kephart and Luther E. Talbert were co-authors of the article, 'Association analysis of stem solidness and wheat stem sawfly resistance in a panel of North American spring wheat germplasm' submitted to the journal 'Crop sciences' which is contained within this thesis. [PUBLISHED]The wheat stem sawfly, Cephus cinctus Norton (WSS), has been a serious pest of wheat in the Northern Great Plains of North America for decades. Host plant resistance has been most consistently effective and is the foundation for integrated pest management of the WSS; therefore, the main objective of this research was to enhance the repertoire of genetic resistance to WSS available for exploitation by wheat breeders through marker-assisted selection (MAS). We used two strategies to achieve our goal. First, we better characterized resistance provided by previously identified quantitative trait loci (QTL). For that, we developed populations of near-isogenic lines (NILs) polymorphic for resistance QTLs on chromosomes 2D (Qwss.msub-2D), 3B (Qss-msub-3BL) and 4A (Qwss.msub-4A.1). Near-isogenic lines were tested greenhouse cage trials and in the field at both WSS-infested and uninfested locations. The Qwss.msub-4A.1 was shown to affect host plant attractiveness to foraging females, but did not change oviposition preference after females landed on the wheat stem. The Qwss.msub-2D and Qss-msub-3BL where shown to be associated with decreased preference for oviposition. The Qss-msub-3BL was also shown to be associated with temporal patterns of stem solidness expression, with the allele derived from the spring wheat cultivar Conan providing decreased infestation, high neonatal mortality, high levels of early stem solidness, and a rapid rate of pith retraction during stem maturation. Together, these studies characterized the effect of each one of these QTLs on WSS resistance. This information will help wheat breeders and entomologists to better integrate management strategies to reduce damage caused by the WSS. Our second strategy, involved the identification of new marker-trait associations for WSS resistance. For that, we used a panel of 244 elite spring wheat lines from North America. By conducting an association mapping study we were able to identify several QTLs for WSS resistance, including QTLs for early and late stem solidness, heading date, stem cutting, and larval mortality. This study showed that improvements in WSS management may be obtained using alleles that already exist in elite germplasm. Collectively, our research provided wheat breeders with a better tool kit for improving resistance to the WSS.Item Impacts of three insect growth regulators and the particle barrier film, Kaolin, on alfalfa weevil, Hypera postica (Gyllenhal), secondary pest, pea aphid, Acyrthosiphon pisum (Harris) & natural enemy complex(Montana State University - Bozeman, College of Agriculture, 2015) Tharp, Cecil Irwin; Chairperson, Graduate Committee: Mary BurrowsStudies were conducted in Montana to evaluate the impacts of the insect growth regulators novaluron, diflubenzuron, azadirachtin and the particle barrier film, kaolin, on the primary pest, alfalfa weevil (AW, Hypera Postica [Gyllenhal)], natural enemies of alfalfa weevil and the secondary pest, pea aphid, Acyrthosiphon pisum (Harris). Kaolin, diflubenzuron and azadirachtin treatments caused low (<53%) AW mortality and did not prevent AW feeding damage across 5 field sites. Novaluron caused the highest mortality (74 ± 3% at one field site) while significantly reducing feeding damage across two of five field sites (P < 0.05) and two greenhouse trials. Plants treated with novaluron weighed significantly more than untreated plants at harvest in either greenhouse study with a final harvest weight of 2.7 ± 0.2 and 3.4 ± 0.3g / pot in the novaluron treated pots compared to 2.2 ± 0.1 and 2.4 ± 0.3 g / pot in the untreated; however harvest yields were not increased in field trials. All experimental treatments provided some pre-harvest benefits to the predator-alfalfa weevil and predator-pea aphid complex at various field sites; however novaluron treatments provided significantly higher predator-alfalfa weevil ratios consistently across four of five field sites when compared to the synthetic pyrethroid, lambda cyhalothrin (P < 0.05). At these four field sites, novaluron treated plots harbored an average predator-alfalfa weevil ratio of 0.15 ± 0.07 compared to 0.02 ± 0.02 in lambda cyahlothrin treated plots in the first harvest cycle. Parasitism rates were significantly higher when experimental treatments were used compared to the lambda cyhalothrin treated plots across five field sites (P < 0.05). The added benefit of conserving predators and parasitoids in combination with direct pesticide efficacy never reduced densities of AW or pea aphid to that of the synthetic pyrethroid treatment in the first or second harvest cycle. While novaluron had little benfit on reducing AW or pea aphid poulations to that of the synthetic pyrethroid treatment, it offers the best potential for developing a soft-chemical/biological system for protecting alfalfa from this key arthropod pest. Future studies taking advantage of novalurons mode of action as a feeding deterrent should be explored.Item Identification of economic wireworms using traditional and molecular methods(Montana State University - Bozeman, College of Agriculture, 2013) Etzler, Frank Eric; Chairperson, Graduate Committee: Michael A. Ivie; Kevin W. Wanner, Anuar Morales-Rodriquez and Michael A. Ivie were co-authors of the article, 'DNA barcoding to improve the species level management of wireworms' submitted to the journal 'Journal of economic entomology' which is contained within this thesis.; Michael A. Ivie was a co-author of the article, 'Review of the Limonius canus LeConte, 1853 (Coleoptera: Elateridae)' submitted to the journal 'The coleopterists bulletin' which is contained within this thesis.Interest in wireworms has grown in the past decade due to their increasing pest status, largely due to the removal of effective seed treatments from the market. Currently, there is no effective Integrated Pest Management (IPM) strategy to control for wireworms, due to the diverse number of species that make up complexes in cropland. The purpose of this study was to determine what wireworm species are present in Montana's croplands and develop tools to make species concepts accessible to non-specialists. This was done using DNA barcoding to associate wireworms with adults. DNA barcoding was done by amplifying the Cytochrome-Oxidase I (COI) region of the mitochondrial genome. Twenty-nine (29) species were successfully sequenced and 13 species had adult and larval associations made, including three new associations. In addition, a LUCID pictorial key was also created to help identify species occurring in Montana. A LUCID key is a computer-based key where a user identifies a specimen with the help of pictures of each character. During the wireworm study, one species-group in the genus Limonius was found to include many economic species, including two that are important in Montana. This group needed to be reevaluated due to controversies raised in a recent revision, many of which dealt with economic species. With the combined use of morphological characters and DNA data, eight species are now recognized as belonging to the group. All of these subprojects show the combined use of DNA and morphology as essential to fully understanding wireworm species. With a more precise knowledge of the species that make up the complexes in Montana's croplands, we can focus on developing IPM stratetgies for efficient control.Item Epidemiology of wheat curl mite (Aceria tosichella K.) and wheat streak mosaic virus on feral grass species and effect of glyphosate on wheat curl mite dispersal(Montana State University - Bozeman, College of Agriculture, 1998) Brey, Christopher WilliamItem Taxonomic studies in the metallic wood-boring beetle family (Coleoptera - Buprestidae - Sphenoptera and Chalcophora)(Montana State University - Bozeman, College of Agriculture, 2010) Maier, Crystal Anne; Chairperson, Graduate Committee: Michael A. Ivie.Taxonomic studies of groups of Sphenoptera Dejean and Chalcophora Solier are presented, resolving several long-standing problems. Species of Sphenoptera of interest for potential use as biocontrol agents for the noxious weed Chondrilla juncea are reevaluated taxonomically. Results of field surveys conducted to increase knowledge of the biology of these species are reported, with little indication of these species' potential for biological control. The Sphenoptera of the former U.S.S.R. are divided into 39 species-groups. Each species group is characterized on adult morphology, illustrations were provided, the member species listed, and distributions noted. Both a classic dichotomous key and an electronic LUCID key are provided for these species-groups to assist in identification. The species-groups Sphenoptera (Sphenoptera) exarata-group and S. (Deudora) rauca-group are revised, with 5 and 7 species respectively. Each included species is redescribed, diagnosed, illustrated, and distribution and taxonomic histories documented. Dichotomous and electronic keys are provided for the species of these species groups. The species Sphenoptera clarescens Kerremans and Sphenoptera egregia Jakovlev are synonymized with Sphenoptera signata Jakovlev and Sphenoptera lateralis Faldermann, respectively. The status of two North American names in Chalcophora Solier -- C. angulicollis (LeConte) and C. virginiensis (Drury)-- is resolved, with both now being recognized as valid. All North American (north of Mexico) Chalcophora are redescribed, diagnosed, keyed, and their nomenclature and distributions reviewed.Item Cultivar susceptibility and fungicide control of black dot root rot(Montana State University - Bozeman, College of Agriculture, 2007) Meyer, Jack Robert; Chairperson, Graduate Committee: Barry J. Jacobsen.Black Dot (Colletotrichum coccodes) is an important potato disease worldwide causing reported yield losses in the 10-30% range. It is involved in the early dying disease complex along with Verticillium dahliae or V. albo atrum, and root lesion nematodes. Besides early dying, black dot also causes silvery blemishes on the tuber surface that resemble those of silver scurf which results in reduced value in fresh markets. The purpose of this work was to evaluate North American cultivars for black dot tolerance and to evaluate fungicides for their efficacy in controlling this disease. To evaluate cultivar resistance, thirty-four commercial cultivars were evaluated in inoculated, greenhouse experiments for susceptibility to C. coccodes. Plant growth was then evaluated 60 days post inoculation. Inoculated plants were stunted and had reduced dry weight of 0% to 53.6% when compared to un-inoculated controls. Significant reductions in growth were observed for 25 of the 34 cultivars (P<0.05).