Life Sciences Commons^™

Differing Short-Term Impacts Of Agricultural Tarping On Soil-Dwelling And Surface-Active Arthropods, Eva Kinnebrew, Victor Izzo, Deborah A. Neher, Taylor H. Ricketts, Kimberly F. Wallin, Gillian L. Galford

Rubenstein School of Environment and Natural Resources Faculty Publications

Agricultural tarping, the practice of placing impermeable plastic tarps over crop beds before planting to suppress weeds, is rising in popularity. However, the use of tarps has uncertain effects on soil arthropod communities. We studied the impact of silage (black plastic) tarps and clear plastic tarps on surface-active and soil-dwelling arthropods by tracking immediate impacts and arthropod recovery for 5 weeks after tarps were removed. We also assessed how well environmental and experimental variables explained arthropod diversity and composition. During tarp application, we found that both silage and clear plastic tarps had significant negative impacts on surface-active arthropod diversity, while …

Metarhizium Anisopliae, Metarhizium Brunneum And Beauveria Bassiana Formulations For Biological Control Of Larval Winter Ticks, Dermacentor Albipictus, Cheryl Sullivan

Graduate College Dissertations and Theses

There is a critical need to develop effective, high-quality, fungal-based biopesticides for use against ticks. Dermacentor albipictus Petch (Acari: Ixodidae), the winter tick, is a one-host tick. They commonly infest large ungulates, particularly moose, Alces alces L. (Artiodactyla: Cervidae) on which they cause significant physiological and metabolic stress on densely parasitized individuals. Heavily infested calves can be killed. Entomopathogenic fungi in the genera Metarhizium (Hypocreales: Clavicipitaceae) and Beauveria (Hypocreales: Cordycipitaceae) are promising tick biological control agents. The larval stage of D. albipictus aggregates on the ground in a prolonged, quiescent state during the summer and then quests for hosts in …

Rapid Evolution In Agroecosystems: Transposable Elements And Epigenetics In The Colorado Potato Beetle, Kristian Brevik

Graduate College Dissertations and Theses

Within agricultural ecosystems, humans and insects enter into complex relationships. Humans consider many of these insects to be pests, and exert significant pressures upon them, such as efforts to kill them using insecticides. One of the ways insects respond to these efforts is by rapidly evolving resistance to insecticides - but how they do this is not fully understood. DNA methylation, an epigenetic mechanism, and transposable elements, which are mobile genetic elements within genomes, may each play a role in shaping the way insects rapidly evolve in response to exposure to insecticides. Understanding the role of transposable elements and DNA …

Evaluation Of Candidate Pheromone Blends For Mating Disruption Of The Invasive Swede Midge (Contarinia Nasturtii), Elisabeth Ann Hodgdon

Graduate College Dissertations and Theses

Swede midge (Contarinia nasturtii, Diptera: Cecidomyiidae) is a small invasive fly that is currently threatening Brassica vegetable and oilseed production in the Northeastern U.S. and Canada. Larvae feed on plant meristems, resulting in deformed leaves, stems, and heads. Extremely low damage thresholds for heading Brassica vegetables, multiple overlapping generations, and lack of effective organic insecticide options present serious challenges for managing this pest. Pheromone mating disruption (PMD), which involves confusing male insects with unnaturally large doses of sex pheromones, is particularly promising for swede midge management because it prevents mating and subsequent oviposition. One major challenge to PMD for swede …

Repelling Contarinia Nasturtii (Diptera: Cecidomyiidae), A Brassica Specialist, Using Non-Host Essential Oils, Chase Stratton

Graduate College Dissertations and Theses

Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), is an invasive pest causing marketable losses on Brassica crops in the Northeastern United States and throughout southern Canada. Heading brassicas, like cauliflower and broccoli, are particularly susceptible because larvae feed concealed inside meristematic tissues of the plant, where head formation occurs. Our work details the development of a sustainable, affordable pest management tactic for swede midge – plant derived repellents.

First, it was necessary to establish both a damage and marketability threshold for swede midge, so we developed a technique to manipulate larval density of swede midge on cauliflower, We asked: (1) …

Enhancing The Efficacy And Thermotolerance Of Selected Beauveria Bassiana Isolates For Management Of Sunn Pest, Eurygaster Integriceps, Using Electrofusion Techniques, Agrin Davari

Graduate College Dissertations and Theses

Sunn Pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), is a major pest of wheat and barley in West and Central Asia and East Europe. The insect causes a significant reduction in yield and quality of grains. Entomopathogenic fungi, especially Beauveria bassiana are among the most dominant microbial agents that have been used against Sunn Pest. However, there are concerns related to their efficacy and thermotolerance particularly in countries with high temperature regimes.

Nine B. bassiana isolates were tested against Sunn Pest to estimate their virulence and speed of infection under laboratory conditions. The isolates were also exposed to 25, 36, 38 …

Distribution, Dna Barcoding And Phylogenetics Of Caribbean Calliphoridae Flies: Tools For Forensic Studies, Sohath Zamira Yusseff

Graduate College Dissertations and Theses

Blow flies (Diptera: Calliphoridae) are among the most dominant and conspicuous insects in the decomposition process. They are important in forensic entomology to determine time of death and, in certain situations, cause of death or relocation of a body. Insects are now included as standard operating procedures in crime scene investigations in many countries, however, this is not standard procedure in the Caribbean area due to lack of knowledge of insects involved in cadaveric decomposition. Successful application of forensic entomology depends on solid underlying data. Our main goal is to advance the knowledge of Calliphoridae in the Caribbean to enable …

Investigating The Effects Of Ant-Hemipteran Mutualisms On The Invertebrate Community Structure And Their Host Plant, Honey Mesquite (Prosopis Glandulosa), Nabil Nasseri

Graduate College Dissertations and Theses

Ants are ubiquitous in most communities and many form opportunistic mutualisms with honeydew-producing hemipterans (e.g. treehoppers). Hemipterans excrete honeydew, a carbohydrate rich substance, that ants harvest and, in return, ants protect their honeydew-producing partners from parasitoids, predators, and competitors. Given the efficacy of tending ants in removing hemipteran antagonists, and the strong roles that ants play within their communities as predators, competitors, and seed dispersers, surprisingly little is known of the effects of ant-hemipteran mutualisms (AHM) on the invertebrate communities in which they are embedded or on the plants that host AHM. Using observational and manipulative field experiments, I examined …

Using Multiple Methodologies To Understand Within Species Variability Of Adelges And Pineus (Hemiptera: Sternorrhyncha), Tav Aronowitz

Graduate College Dissertations and Theses

The species of two genera in Insecta: Hemiptera: Adelgidae were investigated through the lenses of genetics, morphology, life cycle and host species. The systematics are unclear due to complex life cycles, including multigenerational polymorphism, host switching and cyclical parthenogenesis. I studied the hemlock adelgids, including the nonnative invasive hemlock woolly adelgid on the east coast of the United States, that are currently viewed as a single species. I used multivariate morphometric analyses to identify morphological differences among hemlock adelgid lineages. With principal component analyses and MANOVA, the six lineages that were used in this study were found to be significantly …

From Nursery To Nature: Evaluating Native Herbaceous Flowering Plants Versus Native Cultivars For Pollinator Habitat Restoration, Annie White

Graduate College Dissertations and Theses

There is growing awareness about the value of preserving and restoring floral-rich habitats for the benefit of pollinators, especially native bees. The increasing demand for native plants in pollinator habitat restoration and other ecological landscaping applications, combined with the desire for more robust and predictable plant habits, have led to the selection and breeding of native cultivars. Yet, little is known about how these cultivated varieties differ from the native species in their ability to attract and support pollinators. I compared flower visitation by all insect pollinators to 12 native herbaceous plant species and 14 native cultivars in a replicated …

Sexual Conflict And Chemical Communication In Hybridizing Harvester Ants, Michael Philip Herrmann

Graduate College Dissertations and Theses

Sexual conflict occurs when the fitness interests of males and females do not align with one another. The resolution of sexual conflict often depends on the level of control each sex has on the behavior in conflict. In Pogonomyrmex harvester ants with a genetically determined caste system, two separate lineages interbreed with one another during summer mating swarms. Diploid offspring sired by a single lineage develop into reproductive queens, while offspring sired by opposite-lineage parents develop into sterile workers. This results in sexual conflict, as males which mate with opposite lineage queens will produce only workers, resulting in no fitness …

Invasive Plant Ecology In Vermont: Insights From Spatial Analysis And Interactions Of Garlic Mustard (Alliaria Petiolata) With Native Plants And Invertebrates, Chenin Kathleen Limback

Graduate College Dissertations and Theses

Causes and patterns of invasive plant species establishment and success depend broadly upon their ecology, including habitat suitability and interactions with other plants and animals. Here I examine the traits and distribution of invasive plants in Vermont, using spatial analysis, laboratory and field studies. I used GIS to investigate environmental factors correlated with presence of 19 invasive plant species in Vermont campgrounds. My results support the assumption that human dispersal of invasive plant seed and stock may be more important than natural dispersal of these plant species to new sites. I also investigate in-depth the relationships of invasive herbaceous garlic …

Swede Midge, Contarinia Nasturtii (Diptera: Cecidomyiidae), Response To Brassica Oleracea In Simulated Intercropping Systems, Gemelle Laureen Brion

Graduate College Dissertations and Theses

Monoculture agriculture has developed as a result of the Western agricultural growth model, which emphasizes reduced on-farm labor and maximum yield. As a result soil health, which is reliant on a diversity of soil-dwelling organisms, is compromised, pest problems are intensified, and biodiversity is lost when vast land areas are devoted to simplified vegetation schemes. There has been a tremendous rise in interest in alternative cropping schemes. The traditional practice of intercropping has received renewed interest as the emphasis on agricultural growth shifts from a purely development-based model to one of conservation and enhanced biodiversity.

Although intercropping has shown promising …

The Efficacy And Non-Target Impacts Of An Organic Disease Management System Containing Biostimulants Compared With Two Sulfur-Based Systems On Four Apple Cultivars In Vermont, Ann L. Hazelrigg

Graduate College Dissertations and Theses

Disease management in organic apple orchards in Vermont is focused on controlling diseases with sulfur fungicides. The objective of this two year study was to evaluate the target and non-target effects of an organic disease management system containing agricultural biostimulants compared to two sulfur-based systems on foliar and fruit diseases, pest and beneficial arthropods, tree growth, yield and fruit quality on four cultivars, `Ginger Gold', `Honeycrisp' and `Liberty' and `Zestar!'. Trees were arranged in a complete randomized design of five three-tree replications in a certified organic orchard. The two sulfur-based systems differed in the number of applications; in the third …

2013 Annual Report Of Uvm Extension And The Vermont Agricultural Experiment Station, Uvm Extension And Vermont Agricultural Experiment Station

Annual Reports

2013 Annual report of outreach and research from UVM Extension and Vermont Agricultural Experiment Station.