According to UGA Extension Viticulture blog, University of Georgia Cooperative Extension Fruit Disease Specialist Phil Brannen says powdery mildew is just starting to show up on untreated plants in the research grape vineyard at Blairsville, Georgia.
“I hope you will not see it yet in well managed vineyards, but recent rains and other difficulties may have hampered spray programs,” Brannen said.
Spray programs need to be applied on a 7-to-10 day interval when rain events occur as often as they are. Growers also need to use the more efficacious materials at critical infection periods such as bloom and early cover sprays.
It’s important to scout your vineyards and make sure to contact your local county agent should you have questions concerning this disease or others. The 2020 Southeast Regional Bunch Grape Integrated Management Guide can be found at small fruits. It contains valuable information related to the timing and efficacy of fungicides for powdery mildew.