Signs of powdery mildew include white fungal growths on leaves and leaf sheaths. Glumes and awns also can be infected when the disease is severe. Fungal growth is largely limited to outer plant surfaces and can be easily wiped away by rubbing a finger across affected areas. Mature areas of fungal growth may have dark, reproductive structures mixed with the white, cottony growth of the fungus.

Management: Genetic resistance, foliar fungicides.