WSU Extension

Hortsense

Yew
 
Insect
Cottony camellia scale 
Lecanium scale 
Root weevils 



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


Biology
The adult cottony camellia scale is a flat, oval, brownish insect. It is also found on holly and camellia. The scales overwinter on twigs or needles. In the spring, adult females lay cottony egg masses on the underside of needles. The yellowish crawlers (immature scales) feed on the needles. Feeding cottony camellia scales produce large amounts of honeydew, a sweet, sticky material which often develops a growth of dark sooty mold. Honeydew may also attract ants. Foliage with scale infestations may turn yellowish or pale. The cottony camellia scale is also commonly found on holly and camellia.
Management Options


Non-Chemical Management
  • Prune out and destroy heavily infested twigs, when practical.
  • Encourage natural enemies of scales, including ladybird beetles and parasitic wasps. Avoid use of broad-spectrum insecticides which kill these beneficial insects.
  • Control honeydew-feeding ants, which may protect scales from predators.
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
  • Hi-Yield 55% Malathion Spray
    Active ingredient: malathion  |  EPA reg no: 7401-10-34911
  • R-T-U Year-Round Spray Oil
    Active ingredient: oil/pet distillate  |  EPA reg no: 6218-78
  • 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.
Images

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Caption: Cottony camellia scale on yew
Photo by: A.L. Antonelli