Cherry: Leaf spot

Biology

Leaf spot of cherry causes purple to reddish-brown spots on the leaves. The spots are up to 1/10″ in diameter. In wet weather, the underside of the spots may produce cream-colored to pinkish masses of spores. Leaves may also turn yellow and drop soon after infection, or drop prematurely in the fall. This disease can result in minor to severe defoliation, which may affect fruit development. Spots sometimes occur on fruit stems, causing fruit to drop. Occasional infections occur on fruit. Mild, wet weather during the summer increases incidence of disease. The fungus overwinters in fallen diseased leaves. Sour cherries and sweet cherries grown west of the Cascades are more commonly infected.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

• Rake and destroy fallen leaves.
• The application of nitrogen to the leaves in the fall will enhance the decomposition of the fallen leaves.

Chemical Management

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

• Apply fungicides just before blossoms open, at full bloom, and when most or all of the blossom petals have fallen.
• Do not use sulfur products during bloom west of the Cascades.
• Applications made to control brown rot will also control cherry leaf spot.
• Homeowners should not make foliar applications to trees over 10 ft tall.
• Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Approved Pesticides

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

• Bonide Fung-onil Multi-Purpose Fungicide Concentrate
  Active ingredient: chlorothalonil [EPA registration number: 60063-9-4]
• GardenTech Daconil Fungicide Concentrate
  Active ingredient: chlorothalonil [EPA registration number: 67572-82-71004]
• Hi-Yield Snake Eyes Dusting Wettable Sulfur
  Active ingredient: sulfur [EPA registration number: 7401-188-34911]
• Lilly Miller Sulfur Dust Fungicide/Insecticide Dust or Spray
  Active ingredient: sulfur [EPA registration number: 802-16]
• Ortho Max Garden Disease Control Concentrate
  Active ingredient: chlorothalonil [EPA registration number: 239-2522]
• Spectracide IMMUNOX Multi-Purpose Fungicide Spray Concentrate
  Active ingredient: myclobutanil [EPA registration number: 9688-123-8845]
• This list may not include all products registered for this use.

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