WSU Extension

Hortsense

Caption: Cottony camellia scale on holly
Photo by: A.L. Antonelli
  
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Holly : Cottony camellia scale
(revision date: 2/14/2019)


Biology
The cottony camellia scale is a flat brownish or yellowish insect about 1/8" in diameter. The scales overwinter on twigs or evergreen leaves. In the spring, the adult females lay cottony egg masses on the underside of leaves. Crawlers (young scales) feed on the underside of leaves. Cottony camellia scales produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a heavy growth of dark sooty mold. Foliage with scale infestations may turn yellowish and appear stressed. Eventually, the plant may become weakened. Cottony camellia scales also infest camellia, yew (Taxus spp.) and occasionally other ornamentals including hydrangea, English ivy, and maple.
Management Options

Non-Chemical Management
  • Remove any cottony egg masses found on leaves.
  • Hand-pick scales when practical to control minor infestations.
  • Prune and destroy heavily infested leaves and branches when practical.
  • Avoid use of broad-spectrum insecticides which may kill natural enemies of scales.
Select non-chemical management options as your first choice!

Chemical Management


Scout for crawlers. Insecticide applications can be effective when applied to control the immature crawlers stage, usually in late spring to early summer. Oils are effective in the delayed dormant period. Use superior type oil sprays only on overwintering nymphs. 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.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • All Seasons Horticultural & Dormant Spray Oil Conc [Organic]
    Active ingredient: oil/pet distillate  |  EPA reg no: 4-80
  • Bonide Systemic Insect Control
    Active ingredient: acephate  |  EPA reg no: 239-2461-4
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-60
  • This list may not include all products registered for this use.
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Caption: Cottony camellia scale on holly
Photo by: A.L. Antonelli
Caption: Cottony camellia scale on holly: close-up
Photo by: A.L. Antonelli