UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

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 given 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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    Detection of Fecal Contamination on Cantaloupes and Strawberries Using Hyperspectral Fluorescence Imagery
    (2006-05-08) Vargas, Angela Maria; Tao, Yang; Kim, Moon; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Fluorescence methods are widely used for investigation of biological materials, and in recent years have also been used to monitor food quality and safety. In this research, fluorescence imaging techniques for detecting fecal contamination on cantaloupes and strawberries were evaluated. Fluorescence images at emission peaks were examined for fecal classification. These images were subjected to further analysis utilizing band ratios and principal component analysis. Two-band ratio images and principal component images, compared to the single-band images, enhanced the contrast between the feces-contaminated spots and untreated sample surfaces. The images exhibited useful results for contamination detection, however, false positives resulting from natural color variation on strawberry surfaces present a problem throughout the methods. This study confirmed the capability of hyperspectral fluorescence imaging in detecting fecal matter on cantaloupes and strawberries and the potential for this method to be used for developing on-line applications.