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Caption: Douglas-fir upper stem canker
Photo by: R.S. Byther
  
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Douglas Fir : Upper stem canker
(revision date: 4/23/2014)


Biology
Upper stem cankers are caused by fungi in the soil. Seedling Douglas fir trees are affected, with the tops of infected trees turning yellow. By fall, the tops turn reddish-brown. Below the discolored portion of the seedling, on the middle or upper stem, a sunken canker can be found. It starts in a bark crevice and expands around the stem, turning red-brown and eventually girdling the tree. See also Douglas fir: Stem cankers.
Management Options

Non-Chemical Management
  • Do not over-fertilize or irrigate late in the season to prevent susceptible fall growth.
  • Space seedlings well apart to discourage spread of disease.
  • Do not plant in contaminated soil.
  • Remove and destroy infected seedlings.
Select non-chemical management options as your first choice!

Chemical Management


Apply from mid-July to bud set in the fall. Make applications at intervals listed on the product sheet. 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 Fung-onil Multi-Purpose Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 60063-9-4
  • GardenTech Daconil Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 67572-82-71004
  • Ortho Max Garden Disease Control Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 239-2522
  • This list may not include all products registered for this use.
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Caption: Douglas-fir upper stem canker
Photo by: R.S. Byther