Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    DEVELOPING A PERRENIAL LIVING MULCH SYSTEM FOR MANAGING PESTS AND AUGMENTING NATURAL BIOCONTROL IN MARYLAND CANTALOUPE SYSTEMS
    (2022) Nunez, Demian Antonio; Hooks, Cerruti RR; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study investigated how alsike clover (Trifolium hybridum) and Virginia wildrye (Elymus virginicus), when interplanted as a living mulch with cantaloupe, (Cucumis melo var. cantalupensis) would impact herbivorous and beneficial arthropod numbers. An additional objective was to determine how these living mulches would impact fruit yield and quality. It was hypothesized that there would be a reduction of cantaloupe pest herbivores and increase in natural enemy abundances in the interplanting compared to monoculture cantaloupe system. Some arthropods conformed to these expectations. However, most had a neutral or inconsistent response to the living mulches. Striped cucumber beetles (Acalymma vitattum), a major pest, were unaffected by the living mulches on most sampling dates. During several periods in both study years, leaf piercing herbivores including aphids were found in greater numbers on cantaloupe interplanted with clover than wildrye and/or monoculture. Spiders were found in greater abundance in cantaloupe interplanted with clover than wildrye or monoculture plantings during several sampling periods. Other natural enemy guilds such as parasitic wasps and piercing predators were inconsistently influenced by living mulch types. Yield was highest in the monoculture plots and living mulch was correlated with changes in fruit texture and color.
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    AGRICULTURAL DRAINAGE DITCHES AS SOURCES OF BENEFICIAL SPIDERS TO ENHANCE CONSERVATION BIOCONTROL IN ADJACENT CROPLANDS
    (2020) Kutz, Dylan James; Lamp, William O.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Agricultural drainage ditches are uncropped areas on farms located above high-water tables to assist in the hydrologic control of croplands. Drainage ditches have increasingly become the subject of research as sources of beneficial arthropods for agroecosystems. Spiders, the most common generalist predator in most field crops, are an important component of conservation biocontrol, but little is known of spider assemblages in drainage ditches or the extent they colonize adjacent croplands from these ditches. To better understand the composition and population dynamics of spider assemblages in drainage ditches, my objectives were (1) to assess the structure of spider assemblages inhabiting drainage ditches in Maryland and (2) to determine how spider assemblages in drainage ditches and adjacent soybean fields change throughout the soybean growth cycle. Overall, my work contributes to understanding how valuable drainage ditches are as habitats for natural enemies like spiders and how ditches influence spider assemblages in adjacent croplands.
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    Can Cover Crop Residues Suppress Pests and Improve Yield in Eggplant?
    (2018) Coffey, Peter Lawson; Hooks, Cerruti RR; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Field studies were conducted over three growing seasons to investigate the effects of planting eggplant following three winter cover crop treatments on the abundance, predation, and colonization of Colorado potato beetle (Leptinotarsa decemlineata) and flea beetle (Epitrix spp.) abundance. Colorado potato beetle densities were observed to be significantly higher in the early season, and lower in the mid- and late- season when eggplant was planted into a crimson clover residue, compared with a crimson clover – rye mixture or bare ground control. Flea beetle abundance was significantly higher in treatments planted with a winter cover crop. Seedbed preparation treatments for weed control did not significantly affect pest abundance. These results contrast with previous research, raising new questions about how cover crop mixtures interact with pests, and how suppression methods influence the effects cover crops have on arthropod populations.