WSU Extension

Hortsense

Spruce
 
Disease
Oil discoloration of foliage 
Rhizosphaera needle cast 
Rust 
Insect
Coneworms 
Cooley spruce gall adelgid 
Douglas fir tussock moth 
Pine needle scale 
Spruce aphid 
Spruce bud scale 
Spruce budworm 
Spruce needleminer 
Spruce spider mite 
White pine weevil 



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Caption: Spruce bud scale
Photo by: A.L. Antonelli
  
Spruce : Spruce bud scale
(revision date: 4/11/2018)


Biology
Spruce bud scales are reddish to brown in color and occur at the base of new shoots. They tend to be very inconspicuous, as they may be partly hidden by the bark. Lower branches are often heavily infested and may be killed, while upper branches are much less affected. Spruce bud scales produce large amounts of honeydew which is often covered with black sooty mold.
Management Options


Non-Chemical Management
  • Hand removal may help control spruce bud scales on small trees.
  • Do not prune branches unless they are dead.
Select non-chemical management options as your first choice!

Chemical Management

Apply in early summer when crawlers are present. Oil applications should be made during the delayed dormant period (usually some time in February). Horticultural oils, soap-based products and some other products may cause discoloration of spruce needles, particularly on Colorado blue spruce. Read labels carefully and test on a small area before application. DO NOT APPLY Safer Brand Insect Killing Soap Concentrate II to Colorado blue spruce. 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
  • Ortho Volck Oil Spray Dormant Season Insect Killer Conc
    Active ingredient: oil/pet distillate  |  EPA reg no: 239-16
  • R-T-U Year-Round Spray Oil
    Active ingredient: oil/pet distillate  |  EPA reg no: 6218-78
  • 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: Spruce bud scale
Photo by: A.L. Antonelli