Predictive model testing for downy mildew

Wine grapes have been planted for some time in the Southeast, but the industry is expanding into new areas. The UGA Carl Vinson Institute predicted $585 million in business revenues from the winery industry over the next 20 years. The tourism that Georgia vineyards generate is equally or more important than the wine itself. Due to a wet climate, downy mildew is a major disease of wine grapes in Georgia. On multiple occasions, wine grape producers have had 100 percent defoliation of vines due to this disease, resulting in winter kill and poor return bloom the following year. Through collaborations with Italian scientists, UGA plant pathologists tested a downy mildew predictive model (developed in Italy) in 2011 and 2012. Warnings provided during the testing phase allowed producers to adjust their fungicide programs, resulting in significantly less disease pressure and losses due to downy mildew. The information derived from the testing of downy mildew predictive models has allowed growers to both identify and respond to this imminent threat. As such, downy mildew was virtually nonexistent in vineyards that responded to the warnings, despite ideal environmental conditions for disease development.