Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
5 results
Search Results
Item Exploring the potential of entomopathogenic nematodes against wireworms in Montana(Montana State University - Bozeman, College of Agriculture, 2020) Sandhi, Ramandeep Kaur; Chairperson, Graduate Committee: Michael A. Ivie; David Shapiro-Ilan, Anamika Sharma Gadi V P Reddy were co-authors of the article, 'Efficacy of available entomopathogenic nematode strains against Limonius californicus (Mannerheim)' in the journal 'Biological control' which is contained within this dissertation.; Ratnasri Pothula, Satyendra K. Pothula, Byron J. Adams, Gadi V.P. Reddy were co-authors of the article, 'First record of native entomopathogenic nematodes from Montana agroecosystems' in the journal 'Journal of nematology' which is contained within this dissertation.; David Shapiro-Ilan and Gadi V.P. Reddy were co-authors of the article, 'Montana native entomopathogenic nematode species against Limonius californicus (Coleoptera: Elateridae)' in the journal 'Journal of economic entomology' which is contained within this dissertation.; David Shapiro-Ilan, Gadi V P Reddy and Michael A. Ivie were co-authors of the article, 'Efficacy of entomopathogenic nematode infected insect cadavers against wireworms in greenhouse and field' submitted to the journal 'Pest management science' which is contained within this dissertation.; Gadi V P Reddy, David Shapiro-Ilan and Michael A. Ivie were co-authors of the article, 'Effect of soil texture, soil moisture, and soil temperature on efficacy of entomopathogenic nematode strains against wireworms under laboratory conditions' submitted to the journal 'Journal of applied entomology' which is contained within this dissertation.Wireworms (Coleoptera: Elateridae), are important soil-dwelling pests and have become a serious threat to spring wheat in the Northern Great Plains because of lack of effective control measures, creating a need for alternative control methods such as biological control with entomopathogenic nematodes (EPNs). Ten EPN strains were tested against sugarbeet wireworm, Limonius californicus (Mannerheim) in laboratory bioassay. Out of these ten strains, Steinernema carpocapsae (Weiser) (All and Cxrd strains) and S. riobrave Cabanillas, Poinar, and Raulston (355 and 7-12 strains) were found effective in laboratory and shade house. However, the dose required to kill at least 50% of the treated L. californicus larvae was 200 infective juveniles/cm 2. Two Montana native EPN species (S. feltiae and Heterorhabditis bacteriophora) were extracted and were evaluated against L. californicus in laboratory and shade house. Although, 50% mortality was observed due to S. feltiae isolates in laboratory conditions, none of the two isolates of S. feltiae performed well against L. californicus in shade house. Steinernema carpocapsae and S. riobrave in the form of infected Galleria mellonella L. cadavers were evaluated against wireworms (L. californicus and H. bicolor) in field and greenhouse. In field, none of the four EPN strains were found effective in reducing wireworm populations or protecting crop yield in both spring wheat and barley fields. However, only one infected Galleria cadaver of S. carpocapsae (All and Cxrd) and S. riobrave 355 was able to kill wireworm larvae as well as reduce wheat plant damage in greenhouse. The imidacloprid treatment enhanced the infection and killing ability of EPNs against L. californicus. Steinernema carpocapsae All and Cxrd were able to kill 30-46% of L. californicus larvae in all four soil types tested as compared to S. riobrave 355 and 7-12 strains, when maintained at field capacity moisture levels. However, S. carpocapsae All and Cxrd strains were able to infect 35-50% wireworm larvae in sandy loam and clay loam soil type at standardized moisture (18%). Steinernema carpocapsae All and Cxrd killed greater wireworm numbers at 16% moisture level and 25 °C as compared to other moisture and temperature levels in sandy clay loam soil. These results indicate that EPN based strategies could be useful for wireworm management but need to be explored further under field conditions. This strategy can at least be part of a large Integrated Pest Management system for wireworm control in Montana.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 The pathogenicity of Fusarium spp. to Wheat Stem Sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae)(Montana State University - Bozeman, College of Agriculture, 2008) Sun, Zhitan; Chairperson, Graduate Committee: David K. WeaverThe wheat stem sawfly is the most destructive insect pest in both winter wheat and spring wheat production in the northern Great Plains. The sawfly is univoltine, and spends all immature stages within protective wheat stems, which explains the difficulty in controlling populations. However, the almost continuous inhabitation of stems also makes larvae more vulnerable to invasion by microorganisms colonizing both living stems and postharvest stubble. Fusarium spp. were frequently isolated from fungalcolonized larval cadavers, and were found to be the major lethal factors for overwintering larvae in both laboratory emergence experiments and field surveys over three years. The pathogenicity of single isolates of three Fusarium spp., including F. pseudograminearum, F. culmorum, and F. acuminatum, was evaluated against overwintering larvae in sawflycut stems and against actively-feeding larvae in growing winter wheat plants over two years. The tested Fusarium isolates caused twenty to sixty percent mortality in overwintering larvae, and caused forty to eighty percent mortality in actively-feeding larvae. The Fusarium isolates also caused decomposition of sawfly-cut stems and disease in wheat plants, which reflected the versatility of Fusarium isolates acting as saprophytes, entomopathogens, and phytopathogens. Deoxynivalenol was detected in wheat stem tissues colonized by the Fusarium isolates from two years of field experiments, and deoxynivalenol caused toxicity and inhibited the growth of second and third-instar actively-feeding larvae in laboratory bioassays. Wheat grower observations of greater sawfly infestation in dryland wheat fields led to assessment of larval mortality from Fusarium infection in both dryland and irrigated wheat fields. This was studied using cage experiments or field surveys at different locations for three years. Parasitoid attack and fungal infection, mainly by Fusarium spp., were found to be the major lethal factors for developing and overwintering larvae, respectively. There was no difference in sawfly survival in dryland or irrigated wheat fields. As ubiquitous soil microorganisms and plant pathogens, Fusarium spp. impact wheat stem sawfly populations in the field each year.Item 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.