How to Manage Pests
Pests in Gardens and Landscapes
Powdery mildew—Erysiphe polygoni
Older leaves and leaf petioles of plants with powdery mildew may be covered with a white powdery growth.
Young leaves develop small circular white powdery spots that slowly enlarge to cover the leaflets. A slight
chlorosis or yellowing may appear on leaves infected by the fungus.
In most cases, planting resistant varieties or avoiding the most susceptible varieties and following
good cultural practices will adequately control powdery mildew. Plant in unshaded areas as much as possible.
Provide enough water and avoid excess fertilizer. Where infection is limited, prune out and bury or discard
diseased tissue as soon as it appears. If extensive, applications of sulfur may be used.
For more information see the Powdery
Mildew Pest Note.
(left) and 4 mildew infected carrots