Integrated Pest Management
Juniper Scale
Carulaspis juniperi
Juniper scales (U.S. National Collection of Scale Insects Photographs, USDA Agricultural Research Service, Bugwood.org)
Juniper scales (Joseph LaForest, University of Georgia, Bugwood.org)
Juniper scale damage (Joseph LaForest, University of Georgia, Bugwood.org)
Pest Description
- males: narrower, longer, whiter than females; oyster-shaped
- females: 1/16 inch; yellowish brown to white; circular
- immatures: crawlers (mobile stage) 3/64 inch; yellow orange; no wings
- immatures: nymphs (sessile stage) resemble adults, but are smaller
Host Plants, Diet & Damage
- juniper, cypress, false cypress, incense cedar, northern white cedar
- feed on the sap from needles/scales
- affected foliage turns “off-color,” yellow to brown
- new growth may stop
- serious infestations can cause tree death
Biology, Life Cycle & Damaging Life Stage
- overwinter as fertilized females
- crawlers present late-May to late-June
- males and females both form scale coverings and remain stationary; males become mobile during mating
- one generation per year, maybe two in warmer regions
- nymphs and adults are the damaging stages
IPM Recommendations
- Keep trees healthy and stress free.
- Monitor scale crawlers from late-May to late-June using double sided tape wrapped around twigs.
- Apply horticultural oil to smother scales or scale crawlers when monitoring indicates crawlers are present.
- Apply a systemic dinotefuran soil drench, granules or bark band in May.
- Imidacloprid is ineffective against hard scales.