Most landscapes have plants that regularly become diseased with one of the powdery mildew fungi.
Although the fungi involved are usually different on different plants, all of the powdery mildews are similar in appearance. In most cases, prompt recognition and control actions can prevent severe damage to plants from the powdery mildews. Symptoms Powdery mildews, as the name implies, often appear as a white or gray growth of fungus over the leaves, stems, or flowers of affected plants. Young foliage and shoots may be particularly susceptible. Leaf curling and twisting may be noted before the fungus appears.