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IPM Scouting in Woody Landscape Plants

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Euonymus scale - Unaspis euonymi
IPM scouting in woody landscape plants > euonymus scale
Hosts: Evergreen species of euonymus, as well as pachysandra, English ivy and boxwood. It is not found on burning bush. Mature females overwinter on stems and leaves. They begin to produce eggs under the scale coverings in early spring. Eggs hatch in late May to early June, and crawlers emerge for about 2 to 3 weeks. There may be 2 to 3 generations per year. Evidence of scale infestation includes yellow spots on leaves, defoliation, and a heavy crust of scales on the stems. Severe infes-tations can kill the plants.

Management: Target the crawler stage for treatment with horticultural oil. Look for the first generation of crawlers from around the time black locust is in full bloom to when Japanese tree lilac and catalpa are in bloom. The second-generation crawlers emerge in mid-August. The twice-stabbed lady beetle, Chilocorus kuwanae, is an introduced natural enemy of euonymus scale.

Female euonymus scale Male eunymus scale
Female scale (left) is gray to brown, male (right) is slender and white; both are about 2 mm long. The two yellow objects by the female are crawlers.
Additional information
This information was developed from A Pocket IPM Scouting Guide for Woody Landscape Plants by Diane Brown-Rytlewski. Purchase this in a pocket-sized guide for reference in the orchard from MSU Extension (publication E-2839).
The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the Michigan Agricultural Experiment Station, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.
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Updated 10/08/07