Powdery mildew is just starting to show up on untreated plants in the research vineyard at Blairsville, GA. The photograph below was taken today, but infections likely started occurring some time ago. I hope you will not see it yet in well managed vineyards, but recent rains and other difficulties may have hampered spray programs. When rain is occurring frequently, tighten your spray programs to 7-10 day intervals, and use the more efficacious materials at critical infection periods such as bloom and early cover sprays. 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 www.smallfruits.org, and it contains valuable information relative the timing and efficacy of fungicides for powdery mildew.

Early powdery mildew on grape leaf. Note the white fuzzy patches on the upper side of the leaf (photo courtesy of Brooke Warres; UGA Plant Pathology).
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