Infected leaves are somewhat distorted in shape and are covered with a faint gray colored dusty material. Powdery mildew infected nuts or leaves are not significantly damaged by the fungus. Its feeding is limited to the outer cells of the shuck. This does not restrict the movement of nutrients into the developing kernel. Fungicides applied in the course of the regular scab spray program will control powdery mildew.
Infected leaves turn brown along the leaf margin or tip.
The necrotic areas may extend from only a small area at the leaf margin to completely encircle the margin of the leaf. As the lesion matures it becomes gray. Infection can result in leaf shedding from mid July to mid August. Symptoms develop on a few leaves and then spreads to nearby leaves. Seldom is the entire tree affected.