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Caption: Euonymus scale
Photo by: Unknown
  
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Euonymus : Euonymus scale
(revision date: 3/10/2017)


Biology
Euonymus scale females are dark, 1/16" long, and mussel-shaped. The males are narrow, elongate, and white. Euonymus scales are found on both leaves and stems. Infested leaves develop yellow to white spots from scale feeding. Crawlers are orange and first emerge in the spring (there are 2-3 generations/year) from beneath the shells of overwintering mature females. Euonymus scale is also reported to infest bittersweet (Celastrus spp.) and pachysandra.
Management Options

Non-Chemical Management
  • Plant resistant species. Euonymus alata (especially 'Compacta') and E. fortunei 'Acutus' are seldom infested. Several other species will tolerate scale feeding.
  • Do not plant E. japonica (evergreen euonymus), as it is extremely susceptible to scale infestations.
  • Prune and destroy twigs with isolated heavy infestations.
  • Hand-wipe to help control small infestations, when practical.
  • Natural predators may help control infestations, but may not prevent damage.
Select non-chemical management options as your first choice!

Chemical Management


Apply to control the immature crawler stage in May and again in June or July if needed. 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.
  • All Seasons Horticultural & Dormant Spray Oil Conc [Organic]
    Active ingredient: oil/pet distillate  |  EPA reg no: 4-80
  • Bonide Systemic Insect Control
    Active ingredient: acephate  |  EPA reg no: 239-2461-4
  • Hi-Yield Dormant Spray
    Active ingredient: oil/pet distillate  |  EPA reg no: 7401-428
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-60
  • This list may not include all products registered for this use.
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Caption: Euonymus scale
Photo by: Unknown