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How to Manage Pests

Pests in Gardens and Landscapes

Powdery mildew—Erysiphe polygoni

Powdery mildew usually appears first as yellow spots on the upper leaf surface of older leaves; these spots develop the characteristic powdery growth and symptoms spread to the undersides of leaves and stems. Affected leaves may turn completely yellow, die, and fall off and the fruit beneath may become sunburned.

Life cycle

Solutions

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. Protection of susceptible varieties with applications of sulfur may be necessary where conditions are most favorable for mildew.

For more information see the Powdery Mildew Pest Note.

Spores of powdery mildew
Spores of powdery mildew on pea


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