WSU Extension


Armillaria root rot 
Bacterial canker 
Black knot 
Brown rot blossom blight and fruit rot 
Crown gall 
Cytospora canker 
Dead bud 
Gumming (Gummosis) 
Leaf spot 
Little cherry 
Mottle leaf 
Necrotic rusty mottle 
Powdery mildew 
Prunus necrotic ringspot 
Shothole (Coryneum blight) 
Verticillium wilt 
Witches'-broom (Cherry leaf curl) 
Apple-and-thorn skeletonizer 
Black cherry aphid 
Brown marmorated stink bug 
Cherry bark tortrix 
Cherry fruit fly 
Cutworms and armyworms 
Peachtree borer 
Pear slug (Cherry slug) 
San Jose scale 
Shothole borer 
Spider mites 
Spotted wing Drosophila (SWD) 

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Caption: Powdery mildew on leaf
Photo by: G.G. Grove
Cherry : Powdery mildew
(revision date: 5/7/2015)

Powdery mildew attacks leaves, young shoots, and fruit. This fungal disease initially produces a light green, circular spot on either leaf surface. Later, a characteristic white, powdery coating of the fungus appears, typically on the underside of affected leaves. The affected leaves may become blistered and distorted. Leaves on young shoots are affected first. The shoots may also become covered with the fungus. Diseased tissues are often deformed and stunted. Infected fruits develop round, depressed areas which may not show any fungal growth. Older infections may cover the entire fruit. The fungus can overwinter on the plant or in debris on the ground. Powdery mildew is favored by high humidity, warm days, and cool nights.
Management Options

Non-Chemical Management
  • Space plantings and prune to provide good air circulation.
  • Plant in full sun.
  • Provide proper culture. Avoid heavy use of nitrogen fertilizer which promotes growth of susceptible, succulent shoots.
  • Rake and remove fallen leaves from beneath trees.
  • Avoid overhead watering, particularly when fruit is developing.
  • Carefully prune out and destroy severely infected shoots.
  • Remove infected suckers at base of tree.
Select non-chemical management options as your first choice!

Chemical Management

Apply when petals fall. 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.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bi-Carb Old-Fashioned Fungicide [Organic]
    Active ingredient: potassium bicarbonate  |  EPA reg no: 54705-10
  • Bonide Sulfur Plant Fungicide Micronized Spray or Dust RTU [Organic]
    Active ingredient: sulfur  |  EPA reg no: 4-62
  • Hi-Yield Snake Eyes Dusting Wettable Sulfur
    Active ingredient: sulfur  |  EPA reg no: 7401-188-34911
  • Lilly Miller Sulfur Dust Fungicide/Insecticide Dust or Spray
    Active ingredient: sulfur  |  EPA reg no: 802-16
  • Monterey Horticultural Oil [Organic]
    Active ingredient: mineral oil/pet distillate light  |  EPA reg no: 48813-1-54705
  • Spectracide IMMUNOX Multi-Purpose Fungicide Spray Conc
    Active ingredient: myclobutanil  |  EPA reg no: 9688-123-8845
  • This list may not include all products registered for this use.

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Caption: Powdery mildew on leaf
Photo by: G.G. Grove
Caption: Powdery mildew on fruit
Photo by: G.G. Grove