Entomology Commons^™

Impact Of Plant Defenses And Aphid-Associated Microbes In Modulating Sorghum-Sugarcane Aphid Interactions, Edith Ikuze

Department of Entomology: Dissertations, Theses, and Student Research

Sorghum (Sorghum bicolor) is a vital cereal crop globally, facing challenges from invasive pests such as the sugarcane aphid (SCA; Melanaphis sacchari). To elucidate mechanisms of sorghum resistance to SCA, we examined the role of plant defenses and the influence of aphid-associated microbes in modulating sorghum defenses. Lignin is a complex heterogenous polymer present in nearly all plant cell walls that plays a critical role in protecting plants from various stresses. In this study, we investigated the role of the caffeoyl coenzyme-A O-methyltransferase (CCoAOMT), one of the core enzymes in monolignol biosynthesis pathway that leads to lignin …

Hilling As A Management Tactic And Tool For Understanding Soybean Gall Midge (Resseliella Maxima Gagné), Pragya Gupta

Department of Entomology: Dissertations, Theses, and Student Research

Soybean gall midge (Resseliella maxima Gagné, SGM) emerged as a new species in the United States Midwest in 2019, causing injury to soybean (Glycine max L.) Infestation of R. maxima starts with females laying eggs in the fissures or cracks that develop at the base of soybean during the V2-V3 growth stage. The emerged larvae feed on the stem internally, leading to wilting and death of the plants. With knowledge gaps in biology and behavior, management strategies for this pest are challenging. Hilling is a cultural practice causing soil to cover the base of stems and is …

Pollinator Communities And Their Ecosystem Services At Conservation Grasslands And Adjacent Croplands, Araceli Gomez Villegas

Department of Entomology: Dissertations, Theses, and Student Research

Pollinators are intrinsically linked to the success of unmanaged and managed ecosystems by providing pollination services that aid in the reproduction of wildflowers and many crops. Land use change, habitat loss, fragmentation, and related landscape-level phenomena (for example, increased pesticide exposure) threaten pollinators and have been associated with population declines. In the Midwestern region of the United States, land conversion of native prairies and grasslands to row-crop agriculture has been one of the largest contributors to pollinator habitat loss. Conservation programs, such as the Conservation Reserve Program, have worked towards removing environmentally sensitive lands from agriculture production and enrolling them …

Examining Potential Trade-Offs Between Pest Management And Pollination To Sunflower Production In Nebraska, Luis Ochoa Cadena

Department of Entomology: Dissertations, Theses, and Student Research

Sunflower (Helianthus annuus) is cultivated for oil and seed production worldwide, and the United States produces 2.5% of the world’s oilseed sunflower primarily grown in the Great Plains. In 2022, oilseed and confectionary U.S. sunflower production increased by 48 and 44%, respectively, compared to last year's records. However, sunflower production can be seriously compromised by insect pests. The red sunflower seed weevil (Smicronyx fulvus LeConte) is considered the most serious pests in North America and causes severe economic damage yearly. On the other hand, native bees contribute substantially to sunflower yield. Currently, insecticide applications are the primary tool to suppress …

Wild Bee Utilization Of Engineered Pollinator Habitat In Eastern Nebraska Agroecosystems, Shianne Lindsay

Department of Entomology: Dissertations, Theses, and Student Research

Habitat loss is a leading cause of biodiversity decline globally. Further, loss of natural and semi-natural habitat is a major factor contributing to declines in wild pollinator populations. Among intensive agroecosystems in the Midwestern United States, corn, soy, and small grain fields dominate the landscape and leave limited space available for forb-rich habitat that supports diverse pollinator assemblages to exist and thrive. There are numerous barriers and challenges to integrating pollinator habitat into such agroecosystems and quantitative assessments of impacts on pollinator communities are largely lacking. The establishment of high-quality pollinator habitat can provide both high flower abundance and species …

Adverse Health Impacts On Honey Bee (Apis Mellifera L.) Colonies From A Contaminated Environment And Resources, Rogan Tokach

Department of Entomology: Dissertations, Theses, and Student Research

Honey bees (Apis mellifera L.) continue to experience high annual declines due to a combination of factors including pesticides. Due to increasing agricultural intensification has led to a reliance on systemic pesticide treated seed which can brought back to the colony in pollen and nectar. Treated seed is not subject to the same guidelines as pesticide applications reducing the regulations on the disposal of treated seed. In 2015, an ethanol plant in Mead, Nebraska began processing expired treated seed for ethanol production. Subsequently, the University of Nebraska-Lincoln Bee Lab started seeing 100% colony failure in apiaries surrounding the plant. …

First Line Of Defense: Role Of Surface Waxes In Sorghum Defense Against Aphids, Juan David Betancurt Cardona

Department of Entomology: Dissertations, Theses, and Student Research

Since 2013, the sugarcane aphid (SCA; Melanaphis sacchari) has become a devastating pest in sorghum (Sorghum bicolor) in the United States. Efforts to mitigate this pest and contain its rapid population growth have increased recently. Host plant resistance (HPR) is an effective and environmentally friendly strategy to reduce aphid populations in this crop. Many factors make SCA a challenging pest to control. For example, SCA can overcome drastic climatic changes, which allows them to successfully colonize sorghum plants at different developmental stages.

Epicuticular waxes (EW) constitute the first point of contact between plants and their environment. EW …

Interactions Between Resistance Genes In Wheat Triticum Aestivum L. And Wheat Curl Mite Populations Aceria Tosichella Keifer (Eriophyidae), Tran Kim Ngan Luong

Department of Entomology: Dissertations, Theses, and Student Research

Wheat curl mite (WCM) (Aceria tosichella Keifer) is a major pest of winter wheat (Triticum aestivum L.), being the only known vector of three damaging plant viruses, Wheat streak mosaic virus, Triticum mosaic virus, and High Plains wheat mosaic virus. This wheat-mite-virus complex causes significant yield loss globally. Management has been mostly through cultural practices to reduce mite build up in volunteer wheat, thereby reducing the spread of viruses. Host plant resistance to WCM has also been used as an important management strategy for this wheat-mite-virus complex. However, WCM is a cryptic species complex, resulting …

Monarch Butterflies: Rearing Methodologies And The Impact Of Fungicide And Insecticide Exposures, Matthew Greiner

Department of Entomology: Dissertations, Theses, and Student Research

The North American migratory monarch butterfly, Danaus plexippus L., populations has experienced a ca. 90% decline over the past two decades. The decline is attributed to climate change, loss and degradation of overwintering habitat, and the loss of milkweed plants in the midwestern United States. The remaining milkweed stands often occur close to agricultural fields, and efforts to establish additional milkweed on the landscape focus on agricultural systems. However, milkweed plants near agricultural fields are likely exposed to pesticides that could adversely impact monarch caterpillars. Effective management of milkweed habitat supporting monarch caterpillars requires knowledge about the toxicological impacts of …

Integrated Honey Bee Education And Research Aids For Promoting Pollinator Conservation, Courtney Brummel

Department of Entomology: Dissertations, Theses, and Student Research

Extension and outreach programs combine University instruction and research, with off-campus outreach and service to the community. Successful public education requires training in which colleges and their education services provide programs relevant to today’s needs. To better engage with the public, institutions and Extension professionals often partner with private and not-for-profit organizations to provide training opportunities. The following thesis reviews one such partnership with the University of Nebraska-Lincoln and Kimmel Orchard & Vineyard that provides science-focused, on-farm experiences and agriculture production training programming. Chapter 1 reviews their partnership since it began in 2005 and highlights examples of current farm-to-table education …

Developing Regional Extension Programs And Research Tools For Beekeepers, Sheldon Brummel

Department of Entomology: Dissertations, Theses, and Student Research

The body of work presented in this thesis describes the development and structure of the Regional Great Plains Master Beekeeping training program, which started in 2019, serves 1500+ beekeepers across five Midwest states (IA, KS, MO, NE, WY), and is supported through local partnerships and beekeepers. This chapter also discusses the leadership structure and aspects I developed for program advancement and long-term sustainability, such as incorporating mentorship and volunteer service goals as well as requiring independent projects to become a certified Master beekeeper. Independent projects may focus on research or teaching goals but must illustrate the candidate’s ability to apply …

Soybean Gall Midge (Resseliella Maxima Gagné): Insecticide Efficacy And Seasonal Larval Abundance, Vilma Maria Montenegro Castro

Department of Entomology: Dissertations, Theses, and Student Research

Soybean gall midge, Resseliella maxima Gagné was recently identified as a new species injuring soybean in Nebraska, Iowa, South Dakota, Minnesota, and Missouri. Resseliella maxima injury is caused by its three instars that feed on tissues within the soybean stem. Infested plants exhibit a darkening of the stem, disrupting nutrient flow within the plant and can lead to wilting or death of plants. Total yield losses can occur in the first 30 m of the field in heavily infested sites. The biology and behavior of this newly described insects is not well understood and management strategies for the management of …

Stink Bug (Hemiptera: Heteroptera: Pentatomidae) Ecology In Nebraska Agroecosystems, Blessing Ademokoya

Department of Entomology: Dissertations, Theses, and Student Research

Stink bugs (Hemiptera: Heteroptera: Pentatomidae) have gained considerable attention in Nebraska in the last decade due to increasing densities of native stink bug and spread of invasive species in the Midwest. Little is known about stink bug dynamics in Nebraska cropping systems. Based on data from a recent field survey, specimens at the University of Nebraska State Museum and the diagnostic lab of the Entomology Department at the University of Nebraska Lincoln, as well as published literature, we present a checklist of 72 species and subspecies of Pentatomidae (55 Pentatominae, 13 Asopinae, 3 Podopinae and 1 Edessinae) that occur in …

Use Of Attractant And Repellent Semiochemicals To Manage Stable Fly (Stomoxys Calcitrans (L.)) Populations On Pastured Cattle Using A Push-Pull Strategy, Alexander Thomas Lehmann

Department of Entomology: Dissertations, Theses, and Student Research

Stable flies (Diptera: Muscidae) are major economic pests of pastured cattle. Their feeding activity causes billions of dollars of damage to the cattle industry. This project investigated the management of stable flies on pastured cattle using a novel Push-Pull treatment in field trials. The repellent Push treatment, a hydrogenated coconut oil containing approximately 70% of C8, C10, and C12 fatty acids in a starch-pectin water formulation, was applied to the animals weekly. The Pull component was a stable fly trap augmented with an attractant (m-cresol). Permethrin and untreated controls were used as comparisons. Both permethrin and Push-Pull treatments reduced stable …

Examination Of Cajeput Oil (Melaleuca Cajuputi) Phytochemicals As Tools To Manage The Yellow Fever Mosquito (Aedes Aegypti L.), Ellis Johnson

Department of Entomology: Dissertations, Theses, and Student Research

The yellow fever mosquito, Aedes aegypti L., is among the most important insects as it pertains to public health. It vectors several health-endangering pathogens, including yellow fever, dengue fever, chikungunya, and Zika viruses. Insecticides are among the most effective tools used to manage mosquito populations however, their efficacy to manage mosquito populations is being threatened by insecticide resistance. This ongoing threat warrants new chemical strategies to reduce or incapacitate a mosquito population capable of pathogen transmission. Plant essential oils are candidates for identifying novel management tools for disease-vectoring arthropods. Commercially, essential oils have been used for pharmaceuticals, flavoring, fragrances, cosmetics, …

Toxicology Of Chemical Stress To Monarch Butterflies (Danaus Plexippus L.), Annie Krueger

Department of Entomology: Dissertations, Theses, and Student Research

Monarch butterfly (Danaus plexippus L.) population declines have caught the attention of the country and prompted nationwide conservation initiatives. The United States Fish and Wildlife Service has identified insecticide exposure and loss of milkweed (Asclepias spp.) reproductive habitat as primary threats to the monarch. In the Midwestern US, milkweed largely occurs around cropland borders where there may be a spatial and temporal overlap of monarch larvae, insecticide usage, and fertilizer applications. In this study, the acute toxicity and sub-lethal effects on growth and diet consumption of two commonly used pyrethroid insecticides, bifenthrin and beta-cyfluthrin, were characterized …

The Impacts Of Cover Crops Species And Termination Dates On Arthropod Activity In A Corn Production System, Julia N.D. Campos

Department of Entomology: Dissertations, Theses, and Student Research

Cover crops can reduce soil erosion, increase water infiltration, and provide an alternative strategy for weed management in cropping systems. Cover crops change the landscape composition by increasing plant biodiversity, potentially impacting pests and beneficial insects. Ecological principles suggest that cover crop management can influence the arthropods in the subsequent cash crop. However, the impact of management strategies such as cover crop species and termination date on arthropod activity in corn systems is not well understood. The objective of this study was to determine the impact of grass cover crop species (wheat, cereal rye, and triticale) in combination with four …

Characterization Of Western Corn Rootworm (Coleoptera: Chrysomelidae) Susceptibility To Foliar Insecticides In Northeast Nebraska, Timothy B. Dang

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of maize in the United States. A variety of tactics are used to manage this pest such as crop rotation, insecticides, and transgenic maize expressing insecticidal proteins from Bacillus thuringiensis (Bt). WCR populations are highly adaptive and have evolved resistance to these management tactics. Management options are limited as few new tactics are available. Research is needed to evaluate the value of existing tactics used within an integrated framework to manage densities/injury and mitigate resistance.

This study evaluated the field performance of formulated foliar insecticides …

Investigating The Role Of Spiders In Integrated Pest Management For Biological Control Of Nebraska Crop Pests, Samantha Daniel

Department of Entomology: Dissertations, Theses, and Student Research

As generalist predators, spiders are capable of fulfilling a wide variety of ecological niches allowing them to intercept and prey upon an array of insect species. This characteristic could be particularly advantageous within agricultural ecosystems. This project sought to reveal the composition and abundance of spider communities within cornfields in western Nebraska and the impact of agronomic practices on those communities as well as determine the potential for spider predation upon two key pests of corn. Spiders were collected from eight corn fields from May to August 2017 and four corn fields from May to August 2018. Additionally, the populations …

Characterizing The Susceptibility And Biological Fitness Of Nebraska Western Corn Rootworm Populations To Pyramided Plant-Incorporated Protectants, Jordan D. Reinders

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a pest of field corn, Zea mays L., across the United States (U.S.) Corn Belt. Transgenic corn expressing two or more insecticidal proteins (‘pyramid’) derived from Bacillus thuringiensis Berliner (Bt) is a common management strategy employed in areas of continuous corn production. The newest rootworm-Bt pyramid registered in the U.S. is SmartStax^® PRO, which contains two rootworm-Bt proteins (Cry3Bb1, Cry34/35Ab1) and DvSnf7 dsRNA. With the pending commercialization of SmartStax^® PRO, understanding the current susceptibility of Nebraska WCR populations to the Cry3Bb1 + Cry34/35Ab1 pyramid (SmartStax^®) and …

Women In Beekeeping: Impacts Of A Beekeeper Educational Program, Bridget Gross

Department of Entomology: Dissertations, Theses, and Student Research

The decline in honey bee populations over the past two decades in the United States is alarming. The management provided by beekeepers to their honey bee colonies influences the survival of the colony. However, there is a lack of information on the experiences of beekeepers, specifically women beekeepers. The Center for Rural Affairs (CFRA) in Nebraska hosted the “Honey Bees on the Farm: Connecting Women Beekeepers and Women Farmers for Environmental and Economic Benefit” program that provided informal, educational events to women beekeepers and landowners. Using a convergent mixed methods design, the first research question examines the impacts of the …

Effects Of Pesticide Residue Accumulation On Honey Bee (Apis Mellifera L.) Development & Implications For Hive Management, Jennifer Weisbrod

Department of Entomology: Dissertations, Theses, and Student Research

Honey bee (Apis mellifera L.) colonies face annual declines of 40% in the United States. Pesticides play a role in these losses. Pesticide residues picked up from the environment as well as beekeeper-applied compounds may accumulate within the hive. The effects of pesticide accumulation in comb on bee health mitigation of accumulation have not been well-studied. To examine pesticide exposure on health and development, chlorothalonil and the amitraz metabolite N-(2,4-dimethylphenyl) formamidine (DMPF), two pesticides found in hive products, were applied to brood comb. Queen bees were caged onto treated and control comb and egg laying and development were assessed. …

Comparative Physiology Of Honey Bees (Apis Mellifera L.) Exposed To Chlorantraniliprole, Jennifer Williams

Department of Entomology: Dissertations, Theses, and Student Research

One outstanding threat to the honey bee, Apis mellifera L., is the unintended exposure of these pollinators to agricultural pesticides. Anthranilic diamides, such as chlorantraniliprole, work in target pests through activation of the ryanodine receptor causing rapid feeding cessation, lethargy, paralysis, and eventual death. Chlorantraniliprole exhibits low acute toxicity to honey bees but relatively little information exists regarding effects of chlorantraniliprole exposure beyond mortality. The acute toxicity and metabolic detoxification enzyme activities following oral exposure were determined in the honey bee and the model crop pest, the fall armyworm (Spodoptera frugiperda, J.E. Smith). Additionally, chlorantraniliprole effects on honey bee …

Factors Influencing Wheat Curl Mite Aceria Tosichella Keifer Dispersal, Lindsay M. Overmyer

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (Aceria tosichella Keifer) (WCM) is a vector of three plant viruses to wheat (Triticum aestivum L.) including: Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and High Plains wheat mosaic virus. This wheat-mite-virus complex causes significant yield loss in winter wheat across the Great Plains. Management of WCM host plants during the time between wheat harvest and planting of the new wheat crop (the green bridge) is critical in reducing potential risk and loss from this complex. The primary green bridge host, in the central Great Plains, is volunteer wheat. If volunteer …

Surveillance Of Culex And Aedes Mosquitoes In Lincoln, Lancaster County, Nebraska, William Noundou

Department of Entomology: Dissertations, Theses, and Student Research

In 2018, West Nile virus (WNV) was identified as the leading cause of mosquito-borne disease in the continental United States. In response to this very serious problem, the Lincoln-Lancaster County Public Health Department (LLCHD) reinforced their mosquito surveillance program, which constitutes one of the best available tools to fight against this serious threat to human health. The objectives of this study were to 1) expand knowledge of the activity and relative abundance of mosquito communities in understudied areas and 2) evaluate differences in mosquito communities by urban and rural location, especially focusing on known vector species. A total of 6 …

Surveillance Of Culex And Aedes Mosquitoes In Lincoln, Lancaster County, Nebraska, William Noundou

Department of Entomology: Dissertations, Theses, and Student Research

In 2018, West Nile virus (WNV) was identified as the leading cause of mosquito-borne disease in the continental United States. In response to this very serious problem, the Lincoln-Lancaster County Public Health Department (LLCHD) reinforced their mosquito surveillance program, which constitutes one of the best available tools to fight against this serious threat to human health. The objectives of this study were to 1) expand knowledge of the activity and relative abundance of mosquito communities in understudied areas and 2) evaluate differences in mosquito communities by urban and rural location, especially focusing on known vector species. A total of 6 …

From Field To Film: Mosquito Surveillance And Survey Of Us Adults' Knowledge And Attitudes Towards Arthropod-Borne Disease Vectors, Justine Laviolette

Department of Entomology: Dissertations, Theses, and Student Research

Mosquito-borne disease is a public health challenge that warrants an active surveillance program for the identification of mosquito populations and the education of the public for prevention and protection against disease-transmitting arthropods. The communication of science to the public is necessary to prevent disease, change behavior, and promote a dialog between scientists and the public.

People are accustomed to high quality entertainment, which begs the question, “If we made science more entertaining, would the public be more interested?”

To address these issues, the objectives of this study are: 1) identify mosquito species and abundance at the US Meat Animal Research …

Using Adults To Monitor Rnai Susceptibility Of Western Corn Rootworm, Diabrotica Virgifera Virgifera Leconte, Field Populations, Matthew Welter

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is the most damaging corn pest in the U.S. Corn Belt, costing producers over $1 billion annually in control and damage costs. Currently, corn producers rely on three control strategies for WCR management: crop rotation, chemical insecticides, and transgenic corn expressing Bacillus thuringiensis Berliner (Bt) proteins. Populations of WCR have evolved resistance to all of these tactics, limiting effective control strategies for producers. RNA interference (RNAi), is the newest mode of action developed for WCR management. In July 2017, the first RNAi plant-incorporated protectant (PIP) corn product was approved for production …

A Mixed-Methods Study Of Entomology Incorporation In U.S. Secondary Science Instruction, Erin M. Ingram

Department of Entomology: Dissertations, Theses, and Student Research

To encourage understanding and appreciation of insects, entomology education advocates have supported and encouraged K-12 teachers to integrate insects and insect-related content into formal science instruction. However, research examining how and why science teachers incorporate entomology into secondary science courses is limited.

A sequential explanatory mixed-methods research study was conducted to address this gap. The study was conducted in two phases. During the first phase, quantitative survey research was conducted with a representative sample of 254 U.S. secondary life science teachers. During the subsequent qualitative phase, follow-up interviews were conducted with a purposeful sample of 18 survey participants and an …

Promoting Bee Communities Through Habitat Enhancements On Public And Private Lands In Nebraska, Kayla A. Mollet

Department of Entomology: Dissertations, Theses, and Student Research

Wild and managed bees are the most effective pollinators, accounting for about 80% of the pollination of flowering plants and 75% of fruits, nuts, and vegetables in the United States (USDA, 2019; USFWS, 2019). An estimated 4,000 species of bees reside in North America, the majority of which are wild and unmanaged. Wild bee communities are critical for maintaining healthy ecosystems, as they sustain native flora that provides soil stability and habitat for other wildlife. In a changing landscape, floral enhancements on privately and publicly-owned lands may have great impact for improving habitat for pollinators across the United States. Planting …