WSU Extension

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Caption: Pine bark adelgid
Photo by: A.L. Antonelli
  
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Pine : Pine bark adelgid
(revision date: 3/10/2017)


Biology
Pine bark adelgids form woolly or cottony white masses on the trunk, branches, or twigs. Heavy infestations can look like snow on the trunks of trees. Seedling and young trees may have adelgids at the base of the needles or on shoots instead of on the trunks. Needles often become somewhat yellowish (chlorotic). The adelgids are black and short-legged under the white material. Severe adelgid infestations can result in stunting or death of trees.
Management Options

Non-Chemical Management
  • Hand-wipe to control infestations where possible.
  • Wash adelgids from trunks and foliage with a strong stream of water.
  • Encourage natural predators including ladybird beetles, lacewings, and so on.
  • Where practical, remove and destroy heavily infested branches and trees.
Select non-chemical management options as your first choice!

Chemical Management


Esfenvalerate is toxic to bees. Do not apply products containing esfenvalerate on or near blooming plants. To minimize risk to bees, apply in the evening after bees have stopped foraging for the day. Apply in spring to infested bark. 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.
  • Monterey Bug Buster II
    Active ingredient: esfenvalerate  |  EPA reg no: 1021-1778-54705
  • This list may not include all products registered for this use.
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Caption: Pine bark adelgid
Photo by: A.L. Antonelli