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.

Life cycle


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.

Healthy (left) and 4 mildew infected carrots
Healthy (left) and 4 mildew infected carrots

Statewide IPM Program, Agriculture and Natural Resources, University of California
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