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Caption: Douglas-fir twig weevil on noble fir
Photo by: Unknown
  
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Douglas Fir : Douglas fir twig weevil
(revision date: 3/10/2017)


Biology
The Douglas fir twig weevil is a small, wingless, grayish-black beetle with white markings and sometimes pinkish spots. The adult lays eggs in twigs in the summer. The larvae mine under the bark or inside twigs. Infested twigs and small branches often turn a reddish-brown and die back. Small, stressed trees are especially susceptible to attack by the weevils, particularly in dry years.
Management Options

Non-Chemical Management
  • Provide proper culture and minimize stress for trees, especially young ones. Healthy plants are more able to withstand insect feeding.
  • Prune and destroy infested twigs, burning where possible.
  • Hand-pick adults to control minor infestations on small trees, where practical.
Select non-chemical management options as your first choice!

Chemical Management


Apply in July to early August to seedling or small trees. 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.
  • Bayer Advanced Power Force Multi-Insect Killer R-T-S
    Active ingredient: cyfluthrin  |  EPA reg no: 72155-39
  • 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: Douglas-fir twig weevil on noble fir
Photo by: Unknown