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Ornamental Cherry
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Caption: Lecanium scales
Photo by: R.S. Byther
Ornamental Cherry : Scales
(revision date: 3/22/2021)

Various species of scales can attack flowering cherry trees, among them the San Jose scale, a serious pest of fruit trees. Depending on species, scales may be found on the upper or lower surfaces of leaves, or on twigs and branches. Symptoms of scale infestations may include yellowing and/or wilting of leaves on affected plant parts as well as the presence of honeydew, a sweet, sticky material produced by some species of scales. Honeydew, if present, may become covered with a dark growth of sooty mold. Scale insects are generally yellowish to dark brown or gray in color and rounded or oval in shape. They are generally 1/8" long or less.
Management Options

Non-Chemical Management
  • Ladybird beetles and parasitic wasps help control scale populations, but may not prevent damage.
  • Minor infestations may be picked off by hand.
  • Prune and destroy heavily infested branches.
Select non-chemical management options as your first choice!

Chemical Management

Insecticides should be applied to the crawler stage for maximum effectiveness. Oils should be applied during the delayed dormant period to scale species that overwinter as immatures. Oils are not effective on oystershell scale. 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.
  • Hi-Yield Dormant Spray
    Active ingredient: oil/pet distillate  |  EPA reg no: 7401-428
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium salts of fatty acid  |  EPA reg no: 42697-60
  • This list may not include all products registered for this use.

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Caption: Lecanium scales
Photo by: R.S. Byther
Caption: San Jose scale
Photo by: K. Grey