Euonymus: Euonymus scale
categories: Euonymus Euonymus Insects Ornamentals Shrubs
last review date: 2025-12-03 10:06
Photo by: Unknown
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: Visit Home and Garden Fact Sheets for more information on using pesticides.
- 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
Examples of pesticides that are legal for home use in Washington State are listed below.
The list may not include all products registered for this use.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.