WSU Extension

Hortsense

Arborvitae
 
Disease
Berckmann's blight 
Cedar flagging 
Leaf blight 
Shoot tip dieback 
Twig blight 
Insect
Cypress tip moth 
Flat-headed and shothole borers 
Juniper scale 
Juniper webworm 
Leafminers 
Spider mites 
Spruce bud scale 



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Caption: Juniper scale
Photo by: Unknown
  
Arborvitae : Juniper scale
(revision date: 2/14/2019)


Biology
Juniper scale is a small, round, white to gray scale with a yellow dot at the center. Leaves, twigs and branches may be attacked. Symptoms of scale feeding include loss of normal color and luster of foliage, lack of new growth, and yellowing and death of branches. Severe infestations are rare, but may kill plants. The scales excrete large amounts of honeydew, a sweet, sticky material. Honeydew may attract ants, or may become covered with a growth of dark sooty mold. Red cedars and Pfitzer, Irish, and Savin junipers are also commonly attacked.
Management Options


Non-Chemical Management
  • Ladybird beetles and parasitic wasps help control scale infestations.
  • Minor infestations may be wiped off by hand, when practical.
  • Prune and destroy heavily infested branches to help control localized infestations.
  • Provide proper culture. Healthy plants are more able to tolerate damage.
Select non-chemical management options as your first choice!

Chemical Management

Make applications. to control the immature crawlers in late spring to early summer. Do not apply soap products to plants stressed by drought or when tender new foliage is present. Do not apply soap in full sun or when temperatures exceed 90 degrees F. When using Safer Brand Insect Killing Soap Conc II, test a small area for sensitivity before application. 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.
  • 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
  • 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: Juniper scale
Photo by: Unknown