Occurrence: Shaded areas with poor air flow during spring, summer, and early fall.
Distinctive disease growth on surface of the leaves of fine, gray-white, talcum powder usually on the upper surface of the leaves. The growth rapidly becomes dense and may cover the entire leaf.
Conditions Favoring Disease Development: Poor air circulation with high humidity at leaf surface.
Management practices that improve air flow and reduce shading will aid in the reduction of the disease. Reduce length of time water sits on the leaf. Fungicides can be used to control ongoing growth of powdery mildew (follow label instructions particularly relating to timing,