Cindy Preto,* Frank Zalom, and Mysore Sudarshana 
*University of California Davis, CA 95616 (crpreto@ucdavis.edu)

Grape must from vines infected with Grapevine red blotch-associated virus (GRBaV) exhibit negatively altered chemical properties and decreased Brix, collectively resulting in reduced wine quality. Recently, the three-cornered alfalfa hopper (3CAH) was determined to vector GRBaV in a greenhouse study. Before this discovery, limited research had been conducted on 3CAH in California vineyards due to their previous status as only an incidental pest. As a result, there is limited information regarding 3CAH feeding and reproductive hosts in Californian vineyards. I hypothesize that the 3CAH is attracted to vineyards by certain feeding and reproductive weed/cover crop hosts. To test the foundation of this hypothesis, 10 weed species associated with vineyards and 15 commonly planted cover crops were individually caged in the greenhouse with six 3CAH adults (three female and three male) and replicated four times. Feeding and reproductive hosts were determined. Data obtained from this research can be used to generate a list of weeds and cover crops that support 3CAH and an annual succession map to assist growers in management decisions. 

Funding Support: California Department of Food and Agriculture, Specialty Crops Block Grant Program