Euonymus: Euonymus scale
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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
See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.
Non-chemical Management
Select non-chemical management options as your first choice!
- 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.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- 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.
Approved Pesticides
If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.