Drosophila suzukii (Matsumura) (Diptera: Drosophila) is an invasive frugivore and has become a significant pest of small fruit, cherry and grape throughout the United States. It may be possible to determine if a Virginia vineyard is at risk of D. suzukii infestation by analyzing the biotic and abiotic factors around each vineyard. This pest is known to utilize a wide range of cultivated and wild host plants. A host plant survey was conducted at four vineyards in the Piedmont Region of Virginia to identify hosts used by D. suzukii around vineyards. The seasonal availability of host plants and adult emergence from them were tracked. Six host plant species of D. suzukii were identified, some available season-long. Monitoring D. suzukii in cultivated crops is crucial for the timing of spray applications. Homemade and commercially available baits and traps were deployed in two vineyards to determine the efficacy and selectivity towards D. suzukii. The homemade and commercially available baits that contained red wine caught the most D. suzukii, but none were exclusively attractive to D. suzukii. Wine grape susceptibility was assessed in laboratory choice and no-choice ovipositional bioassays. Ovipositional susceptibility was determined by measuring the physiological and morphological parameters using six wine grape varieties. More eggs were laid in grapes as penetration force decreased. Penetration force and not skin thickness was the limiting factor for oviposition. Survivorship of eggs laid in intact grapes was analyzed and survivorship to adulthood was dependent upon variety and survivorship usually exceeded 9% survival seen in previous studies. Larval developmental parameters of D. suzukii were affected by grape variety and the density of Z. indianus. D. suzukii mortality was increased in most cases when in competition with Z. indianus, but was less pronounced when reared in Viognier grapes. My Z. indianus oviposition study demonstrated that they will follow injury created by D. suzukii, and then the Z. indianus larvae may outcompete D. suzukii within the berries. These studies greatly improved our understanding of D. suzukii biology and ecology in Virginia vineyards. / Ph. D. / Drosophila suzukii (Matsumura) (Diptera: Drosophila), henceforth referred to as spotted wing drosophila (SWD) is an invasive pest of small fruits, cherries and grapes grown throughout the United States. This pest has a wide host range including cultivated and wild host plants. A host plant survey was conducted at four vineyards in the Piedmont Region of Virginia to identify those used by SWD. The seasonal availability of host plants and adult emergence from their fruit were tracked throughout the growing season. Six host plant species were found and these host plants were available to SWD throughout the season. Monitoring SWD in cultivated crops is crucial for the timing of spray applications. Homemade and commercially available baits and traps were deployed in two vineyards to determine the efficacy and selectivity towards SWD in the vineyard. Baits containing red wine, whether homemade or commercially available caught the most SWD, but none were exclusively attractive to SWD. Wine grape susceptibility to SWD oviposition was assessed in laboratory no-choice and choice ovipositional bioassays using six wine grape varieties; physiological and morphological parameters were considered. More eggs were laid in grapes as penetration force decreased. Penetration force and not skin thickness was the limiting factor for oviposition. Survivorship of eggs laid in intact grapes was analyzed and up to 50% of the eggs laid in larger grapes survived to adulthood. Larval interactions between SWD and Z. indianus, African fig fly (AFF), were also analyzed based on competition intensity and grape variety in which they were reared. SWD mortality, developmental parameters and pupal volume were impacted when in competition with AFF. SWD mortality was less pronounced, even when in competition with AFF, when reared in Viognier grapes compared to any other grape variety tested. My Z. indianus oviposition study demonstrated that they will flow injury created by D. suzukii and lay oviposit eggs into those wounds. These studies greatly improved our understanding of SWD biology and ecology in Virginia vineyards.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/86414 |
| Date | 22 June 2017 |
| Creators | Shrader, Meredith Edana |
| Contributors | Entomology, Pfeiffer, Douglas G., van der Linde, Kim, Bergh, J. Christopher, Burrack, Hannah J., Samtani, Jayesh B. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
Page generated in 0.0013 seconds