Scouting for insects: Juniper scale

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Juniper scale: Carulaspis juniperi (view photos)

Hosts:
Juniper, arborvitae and chamaecyparis. An infestation of this armored scale causes off-color foliage, yellowing and dieback of juniper needles. Severely infested junipers may have little to no new growth. Female scales overwinter as adults with eggs; there is one generation per year. Look for crawler emergence beginning early to mid-June, around the time Washington hawthorn or Japanese tree lilac is in bloom.

Management:
Several parasitic wasps are among the natural enemies of juniper scale. The overwintering adult female is vulnerable; otherwise the crawler stage should be targeted for treatment with insecticides.
Diane Brown-Rytlewski’s articles are excerpts from "A Pocket IPM Scouting Guide for Woody Landscape Plants."

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