WSU Extension


True Fir
Annosus root rot 
Armillaria root rot 
Current-season needle necrosis 
Grovesiella canker 
Interior needle blight 
Needle casts 
Phytophthora root rot 
Rust (Pucciniastrum) 
Rust (Uredinopsis) 
Balsam twig aphid 
Balsam woolly adelgid 
Giant conifer aphids 
Spruce budworm 
Spruce spider mite 

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Caption: Interior needle blight
Photo by: G.A. Chastagner
True Fir : Interior needle blight
(revision date: 4/23/2014)

Interior needle blight is found primarily on noble fir in Christmas tree plantings, but may also occur in the landscape. While a fungus has been associated with the disease, other factors may also be involved. Needles on the lower branches turn brown, but remain attached to the branches. Affected needles are dropped by spring, resulting in minor to severe defoliation. Affected Christmas trees may be unmarketable, but damage to landscape trees is most likely only aesthetic unless the problem becomes very severe.
Management Options

Non-Chemical Management
  • Provide proper culture. Healthy trees are more resistant to stress and disease.
  • Clear weeds from around trees, and maintain good air circulation in plantings. This reduces many fungal infections, and may be useful.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Interior needle blight
Photo by: G.A. Chastagner