Final Report – Funding Cycle 2021 – 2023 (Three years)
Principal Investigator – Michelle Moyer, Washington State University, Prosser
Co-P.I. – David Gadoury, Cornelle University
Telephone: 509-786-9234
Summary: Dr. Moyer studied UV-C light for integration into powdery mildew management programs in Washington State. A component of her evaluation was to learn if the UV light had any effect on grape mealybug, the primary vector in Washington State of grapevine leafroll associated virus 3. Previous UV-C light research found some control of other insects.
The research objective was to better understand possible suppressive effects of UV-C light on grape mealybug in a controlled environment, which could lead to further exploration. In a lab study, mated grape mealybug females were exposed to various doses of UV-C light applied during darkness and followed by an additional four-hour dark period post-treatment to enhance possible suppressive effects. Control treatments include 2% horticultural oil and no treatment. The treated females were observed two weeks after treatment. Eggs hatched up to four weeks after treatment were counted. In a separate lab study, first instar nymphs were exposed to UV-C light with and without a dark period. Nymph mortality was assessed 24 and 48 hours after treatment.
Although UV-C treatment of mated mealybug females did not affect their egg laying ability, small but significant impacts on nymph mortality were observed and warrant further study.