WSU Extension


Douglas Fir
Armillaria root rot 
Laminated root rot 
Rhabdocline needle cast 
Stem cankers 
Swiss needle cast 
Upper stem canker 
Yellow-green mottle syndrome 
Cooley spruce gall adelgid 
Douglas fir needle midge 
Douglas fir tussock moth 
Douglas fir twig weevil 
Sequoia pitch moth 
Silverspotted tiger moth 
Spruce spider mite 

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Caption: Douglas-fir yellow-green mottle syndrome
Photo by: G.A. Chastanger
Douglas Fir : Yellow-green mottle syndrome
(revision date: 4/23/2014)

The cause of yellow-green mottle syndrome is unknown, but may be genetic. Needles of all ages are affected by yellow-green mottle syndrome. Yellow-green blotches may be small or may cover the entire needle, but the midrib is never affected. Mildly affected needles have small or large blotches on only one side of the midrib. Severely mottled needles are entirely yellow with a dull green midrib. Affected needles usually fall off the trees, sometimes causing severe defoliation. Trees sometimes grow out of the syndrome in two or three years.
Management Options

Non-Chemical Management
  • Give affected trees a chance to outgrow the mottling.
  • Remove and destroy trees that are affected every year.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Douglas-fir yellow-green mottle syndrome
Photo by: G.A. Chastanger