By: Judy O’Mara
Powdery mildew is a common disease on many ornamentals. It is easy to identify because it produces a whitish-gray mold on the surface of the leaf. This fungal disease is favored by high humidity and crowded plantings (i.e. poor air flow). Powdery mildew doesn’t kill the plant but susceptible hosts that have a chronic problem with it can be weakened. The best management strategy is through the use of resistant varieties.
The Home, Yard & Garden newsletter from the University of Illinois has a nice article on powdery mildew this week: http://hyg.ipm.illinois.edu/article.php?id=1092