Powdery mildew (Erysiphe graminis); Gray, fluffy threads of the fungus can be observed on the upper surface of the leaves and leaf sheaths. The fungal strands penetrate and invade the leaf tissue. As the disease progresses, the leaf turns yellow and is gradually killed. Spores of the fungus are carried from plant-to-plant by wind currents. While the disease can be controlled with fungicides, (Table 2) such controls may not be economical. Some resistant varieties are available (Table 1).
