Ultralawn, Inc. 1055 East 260th Street Euclid, Ohio  44132 (216) 731-7756 (440) 951-3738 Lawn Diseases   We welcome the opportunity to answer your questions Powdery Mildew Symptoms: Powdery mildew is common on many kinds of plants. Powdery mildew may appear quite suddenly, usually in shaded areas, and most commonly on Kentucky bluegrass. The grass blades look as if they were dusted with flour. The white to gray powder are spores of the powdery mildew fungus. The fungus grows over the surface of the leaf, absorbing nutrients from the plant. The leaves often support the presence of the powdery mildew fungus for some time without significant injury. Powdery mildew is most common in turf from July to September, and occasionally in the spring. It is most common during overcast periods of cool, moist weather.   Cultural Management: Powdery mildew is usually a disease that affects shaded turf grass. Similar grasses growing nearby in full sun usually will remain free of powdery mildew. To reduce shade and increase air circulation, prune shrubs and tree branches. If grass is thin or weakened in shady areas, re-seed with shade-tolerant grass species. If grass is growing very poorly due to shade, consider its replacement with shade-loving ground covers. In moist, shaded areas of lawns, powdery mildew may be prevented or reduced by careful lawn care. Avoid excess nitrogen fertilizer; raise the mowing height and water deeply but infrequently. Avoid frequent, light sprinkling. Chemical Management: Fungicide treatments are not recommended for powdery mildew control on lawns. Copyright 2010-2011 Updated December 9, 2011 About • Lawn Care • Trees/Shrubs • Pest Barrier • Questions • Contact