Theses and Dissertations at Montana State University (MSU)

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    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.
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    Taxonomic studies on click-beetles (Coleoptera: Elateridae)
    (Montana State University - Bozeman, College of Letters & Science, 2019) Etzler, Frank Eric; Chairperson, Graduate Committee: Michael A. Ivie; Paul J. Johnson was a co-author of the article, 'Athoplastus johnson and etzler (Coleoptera: Elateridae: Dendrometrinae), a new genus of click beetle from the northwestern continental USA' in the journal 'Coleopterists bulletin' which is contained within this dissertation.
    Click-beetles (Coleoptera: Elateridae) have historic difficulties at the subfamilial, tribal, and generic level, with many genera poorly defined at the global scale. This dissertation makes the definitions of four groups work world-wide to enable easier communication between regions. These clearer definitions also serve as foundations for future studies at higher levels, such as the tribal and subfamilial level. In this work, two new genera are described, seven species are described as new, 109 new combinations are proposed, and 5 new names are proposed to correct new homonyms. Keys to species are provided for the North American species in Athoplastus and Hemicrepidius and the species north of Mexico for Paradonus. A key to genera in the Limonius genus-group is provided, with a key to species provided for the newly described genus in that group. Important morphological characters are illustrated for each genus or genus group, and habitus photos are provided for all species in the examined regions for the genera Athoplastus, Hemicrepidius, and Paradonus.
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    The composition of wireworm species in Montana wheat and barley fields and its effect on developing IPM programs
    (Montana State University - Bozeman, College of Agriculture, 2014) Morales-Rodriguez, Anuar; Chairperson, Graduate Committee: Kevin Wanner; Kevin W. Wanner was a co-author of the article, 'An evaluation of four different bait traps for sampling wireworms (Coleoptera: Elateridae) infesting cereal crops in Montana' submitted to the journal 'Journal of economic entomology' which is contained within this thesis.; Ruth P. O'Neill and Kevin W. Wanner were co-authors of the article, 'A survey of wireworm (Coleoptera: Elateridae) species infesting cereal crops in Montana' in the journal 'Pan-pacific entomologist' which is contained within this thesis.; Kevin W. Wanner was a co-author of the article, 'Determining the potential for cereal crop injury by wireworm species commonly found infesting cropland in Montana' submitted to the journal 'Canadian entomologist' which is contained within this thesis.; Kevin W. Wanner was a co-author of the article, 'Efficacy of thiamethoxam and fipronil, applied alone and in combination, to control Limonius californicus and Hypnoidus bicolor (Coleoptera: Elateridae)' in the journal 'Pest management science' which is contained within this thesis.; David Wichman and Kevin W. Wanner were co-authors of the article, 'Effects of cultural practices on wireworm populations and damage in cereal fields' submitted to the journal 'Crop sciences' which is contained within this thesis.
    Wireworms, the larvae of click beetles, are the most important soil-insect pest of small grain fields in Montana. Worldwide, there are about 9,300 species of elaterids in 400 different genera, and in North America 885 species in 60 genera have been identified. In Montana, 166 species were identified, among them, 21 species have been identified as possible pests in small grain fields and some are serious pests of a wide variety of crops. My research focused on three main objectives related to wireworm IPM: first, the identification of the species causing damage in the field and their geographic and seasonal distribution in Montana; second, establishing the potential of different baited traps to monitor pest wireworm populations; and third, evaluating chemical and cultural management alternatives. To complete the first objective a statewide wireworm survey was conducted for three years as well as an intense sampling of four cereal fields season for three consecutive years. To complete the second objective, the effectiveness of four baited traps were assessed: traditional pitfall compared to pot, stocking and canister type traps, in four cereal fields for three years. To complete the last objective, laboratory, greenhouse and field studies were conducted to evaluate new insecticides, crop injury, tillage practices and seeding density. 5,097 wireworms were collected from the four sites during 2010 - 2012 including four common species, Aeolus mellillus, Hypnoidus bicolor, Limonius californicus and L. infuscatus, and three minor species, Agriotes spp., Dalopius spp. and Selatosomus aeripennis. Peak wireworm activity at the soil surface was found to coincide with cereal crop germination and establishment. While all trap types can be used to detect wireworm activity and estimate population levels, pitfall and stocking were more efficient than pot and canister traps. Thiamethoxam does not kill wireworms but its ability to suppress wireworm populations in the field can be improved by the addition of fipronil. Increasing seeding density is one of the most common cultural recommendations for managing wireworms, but my studies did not support its benefit to higher crop yields. Significantly, species-specific crop injury and seasonal movement in the soil support the need for species-specific IPM research.
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    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.
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    Effects of alternative management practices on the abundance of arthropods in a mixed-crop agroecosystem
    (Montana State University - Bozeman, College of Agriculture, 2013) Gill, Paramjit Singh; Chairperson, Graduate Committee: Kevin O'Neill
    We evaluated the effects of alternative management practices on the abundance and diversity of arthropods in a mixed-crop agroecosystem in studies conducted in 2010 and 2011 at the Fort Ellis Experimental Station near Bozeman, MT. In one study, we quantified arthropod relative abundance in plots across three summer fallow weed management practices (sheep grazing, mechanical/tillage, and chemical herbicide) incorporated into a three-year rotation in two different sets of crops. Arthropod abundance was compared among 1) the spring wheat plots under the three management schemes with the rotational treatments (continuous spring wheat and rotational spring wheat), 2) the pea/hay barley plots under the different weed management schemes, and 3) fallow plots under the three weed management schemes. In a second study, we examined arthropod relative abundance in plots with alternative alfalfa cultivars (Cimarron SR, HayGrazer, and Shaw). Sweep net samples were taken to compare the abundances of the most common insect orders and families (as well as a few abundant species and genera). In addition, baited traps were used to compare the abundance of click beetle larvae or wireworms (Coleoptera: Elateridae) within the different management schemes and treatments. This study demonstrated that the number of arthropods in the continuous spring wheat was lower compared to the rotational spring wheat. Arthropod abundance in the pea/hay barley plots under the three different managements was inconsistent from one year to the other. In the summer fallow plots, abundance of most arthropod taxa was the lowest in the mechanically-treated plots, whereas there was no difference in the number of most arthropods present between the chemical and grazed plots which shows that sheep grazing was equally effective as the application of herbicides in reducing arthropod numbers on summer fallow plots. The abundance of most arthropod taxa did not differ among the Cimarron SR, HayGrazer, and Shaw alfalfa cultivars except for Aphididae, Formicidae, and Ichneumonidae in 2010. Nine species of wireworms were collected from the study site with Aeolus mellilus Say being the most common. In both years, A. mellilus was most abundant in the continuous spring wheat plots compared to the other plots.
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