Ornamental Cherry: Leaf spot

Biology

Leaf spot on cherry first appears as small circular, purple spots on the leaves about the time they reach full size. Infections begin in the spring and continue through late summer. The spots turn brown, and enlarge. The centers may drop out, giving a “shothole” appearance to the affected leaves, or the leaves may turn yellow and drop, sometimes resulting in severe defoliation. This fungal disease overwinters on fallen leaf debris and attacks new leaves in the spring. Mild, wet summer weather promotes infection, which can only occur on wet foliage.

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 all fallen leaves and debris under trees.
• Avoid overhead watering. If overhead irrigation is necessary, limit it to times when foliage can dry quickly.
• Space plantings and prune to provide good air circulation.

Chemical Management

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

• Apply fungicide at petal fall, shuck fall and 2 weeks later. (Shuck fall: when flower petals have fallen away from young fruit).
• Sulfur products may cause plant damage if applied at temperatures greater than 85 degrees F.
• 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]
• Defend DF/Home and Garden Use/for Organic Gardening [Organic]
  Active ingredient: sulfur [EPA registration number: 62562-8]
• 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]
• Safer Brand Garden Fungicide/Flowers, Fruit and Vegetables Concentrate
  Active ingredient: sulfur [EPA registration number: 42697-37]
• 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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