Pea: Powdery mildew

categories: Pea Pea Diseases Vegetables

revision date: 2022-12-07 12:00

Powdery mildew on pea.
Powdery mildew on pea
Photo by: R.S. Byther

Biology

Powdery mildew is a fungal disease which attacks the leaves, pods, and stems. Leaves and stems develop discolored spots. The spots later show characteristic white mats of powdery fungal growth which give a bluish cast to the foliage. Small black fruiting bodies of the fungus may be present in the white mats. The infected areas may die on some pea varieties, and some varieties including ‘Oregon Sugar Pod’ may show brown or black necrotic spots on affected pods. Infection early in the season may result in stunted plants. Powdery mildew may result in reduced yields. Warm days, cool nights, and humid weather favor development of powdery mildew, which is often worse in the fall. The fungus may be carried by infected seed, which is often gray-brown in color. It can also overwinter on infected plant debris.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Plant peas early. Spring crops seldom show serious damage. Do not replant fall peas in the same location.
  • Plant resistant varieties such as ‘Almoto’, ‘Aspen’, ‘Concord’, ‘Freezer 604’, ‘Knight’, ‘Sentry’, ‘Sounder’, ‘Super Sugar Melt’ (snap pea), and others.
  • Clean up plant debris in the garden. Destroy or discard (do not compost) diseased materials.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • Apply according to label instructions.
  • Do not apply sulfur products if temperatures are high or leaves may burn.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

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