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."