Powdery Mildew (fungi - Erysiphe spp.): Powdery mildew is especially common on annual grasses used for overseeding. It spreads rapidly in shaded areas. Powdery mildew appears as a grayish-white fungal growth on the upper surface of leaves and leaf sheaths. Infected leaves turn yellow and gradually die. Repeated infestations result in eventual death of plants. Surviving plants are weakened.
Management: Reduced shading and increased air circulation will help control powdery mildew. Where these conditions cannot be changed, fungicides are available for control.