Plant Science & Landscape Architecture Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2797
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Item UNDERSTANDING LATE SEASON FRUIT ROT PATHOSYSTEMS AND INSECT INTERACTIONS IN MID-ATLANTIC VINEYARDS(2016) Kepner, Cody; Swett, Cassandra L; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Fungal fruit rots and insect pests are among the most important problems negatively affecting the yield and quality of mid-Atlantic wine. In pathogenicity trials of fungi recovered from diseased Chardonnay and Vidal blanc grapes, Alternaria alternata, Pestalotiopsis telopeae, and Aspergillus japonicus were found to be unreported fruit rot pathogens in the region. Additionally, P. telopeae and A. japonicus had comparable virulence to the region’s common fruit rot pathogens. Furthermore, a timed-exclusion field study was implemented to evaluate vineyard insect-fruit rot relationships. It was found that clusters exposed to early-season insect communities that included Paralobesia viteana had a significantly greater incidence of sour rot than clusters protected from insects all season. These results were contrary to the current assumption that fall insects are the primary drivers of sour rot in the region. This research provides diagnostic tools and information to develop management-strategies against fungal and insect pests for mid-Atlantic grape growers.Item TRANSMISSION OF CYMBIDIUM MOSAIC VIRUS IN ONCIDIUM ORCHIDS BY PERIPLANETA AUSTRALASIAE(2012) Allen, Carol Dianne; Coleman, Gary; Hammond, John; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)ABSTRACT Title of Thesis: TRANSMISSION OF CYMBIDIUM MOSAIC VIRUS IN ONCIDIUM ORCHIDS BY PERIPLANETA AUSTRALASIAE Carol Dianne Allen, Master of Science. 2012 Thesis Directed by: Gary Coleman, Ph.D. Department of Plant Science and Landscape Architecture Cymbidium mosaic virus is the most common disease in orchids infecting a large number of cultivated orchids found in all phases of the industry and around the world. Its transmission occurs through contact by contaminated cutting tools, human hands, or water. Although insects known to transmit plant viruses have been exposed to orchid viruses, none have been found to successfully transmit Cymbidium mosaic virus. Periplaneta australasiae, the Australian cockroach, is a common greenhouse pest that is known to feed on orchid plants. In controlled conditions Australian cockroaches were given inoculation access through feeding activity on known CymMV positive orchid plants and then allowed to feed on virus free plants. The virus free plants were isolated from subsequent insect exposure and after a period of time samples from the feeding damage sites were analyzed for the presence of virus RNA through nested and hemi-nested PCR techniques. A statistically significant number of samples were positive demonstrating that with high population numbers and long term exposure, virus transmission is possible.