Dissertation
Alternative Pest Management Technologies for Erysiphe Necator and Pseudococcus Maritimus in Vitis Vinifera Wine Grape Production
Washington State University
Doctor of Philosophy (PhD), Washington State University
2023
DOI:
https://doi.org/10.7273/000006395
Abstract
Evaluation of potential alternative pest technologies against economically damaging pests and diseases will answer if they are viable solutions for growers. Two such alternatives, ozonated water spray (OWS) and ultraviolet-C light (UV-C), were evaluated for their ability to control two prominent pests in eastern Washington in Vitis vinifera vineyards: grapevine powdery mildew (causal agent: Erysiphe necator) and grape mealybug (Pseudococcus maritimus). The potential curative effect of OWS on developing E. necator colonies and lethal effects to P. maritimus nymphs was evaluated using ozone concentrations of 1 or 7 mg/L, delivered through a laboratory system. These studies were coupled with field evaluations using a commercial OWS retrofit system for the management for E. necator during the grape pre-bloom season and P. maritimus as a delayed-dormant treatment. Our lab and field studies demonstrated that current OWS systems will not be an effective tool for E. necator and P. maritimus management when applied at ozone concentrations commercial units are currently able to generate. UV-C doses of 100 and 200 J/m2 applied to developing E. necator colonies in lab reduced colony development. In Vitis vinifera ‘Chardonnay’ vineyards, UV-C (200 J/m2) was applied once or twice-weekly under different application regime timings (early-season or season-long). While not always statistically significant in field experiments, the consistent trend in reduction of powdery mildew disease by using UV-C combined with no adverse effects to yield or fruit, suggests that UV-C could be an additional tool for grape powdery mildew management. Lastly, UV-C doses from 100 to 1,000 J/m2 was exposed to mated P. maritimus adult females and first instar P. maritimus nymphs in lab. UV-C treatment of mated adult females did not prevent oviposition or reduce ovisac viability. Increasing doses of UV-C treatments, followed by a dark period, had a small, but significant impact on nymph mortality. While OWS is a commercial technology, its ability to effectively generate and maintain ozone is dependent upon environmental conditions, thus reducing its robustness in the field. UV-C holds better promise and could function as a rotation option in existing commercial fungicide regimes to reduce total chemical pesticide inputs in a vineyard system.
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Details
- Title
- Alternative Pest Management Technologies for Erysiphe Necator and Pseudococcus Maritimus in Vitis Vinifera Wine Grape Production
- Creators
- Alexa Lynn McDaniel
- Contributors
- Michelle M Moyer (Advisor)Lav R Khot (Committee Member)Lisa W DeVetter (Committee Member)Thomas S Collins (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Agricultural, Human, and Natural Resource Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 177
- Identifiers
- 99901087840601842
- Language
- English
- Resource Type
- Dissertation