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What’s Wrong with My Blue Spruce Tree?

blue spruce with cytospora
Blue spruce with symptoms of Cytospora canker.

Dr. Dave Clement, University of Maryland Extension Plant Pathologist, explains two common diseases of this popular evergreen tree. 

Colorado blue spruce trees, although not native or adapted to Maryland, are commonly planted in landscapes for their attractive color and shape. There are, however, two plant diseases that commonly infect and disfigure them. Both diseases also can occur simultaneously and progressively speed up the decline of this popular tree.

Rhizosphaeria needle blight on blue spruce.

Needle Cast or Needle Blight

The most common needle problem of blue spruce in Maryland is a fungal disease caused by Rhizosphaeria kalkoffii.


Dieback or Cytospora Canker

The most common dieback disease of blue spruce in Maryland is caused by the fungal pathogen Leucostoma kunzei.

Blue spruce with dieback from Cytospora.


Infection starts in the spring on wounds caused by pruning cuts, insects, hail damage, or cracks caused by ice, or snow load. The disease causes large amounts of resin flow that appear as white crusty sap streaks on the bark. The infection period can extend from spring through fall depending on rainfall. Drought stressed trees are more vulnerable to this disease.

Practical management of both of these diseases is difficult because the infection period can extend from spring through fall depending on rainfall. Diseased branches can also serve as sources of infective spores for many years after infection and help intensify disease progression. Therefore, fungicide sprays are impractical for most homeowner trees. Severely diseased trees should be removed and replaced with better adapted conifers for the mid-Atlantic region.

Arizona cypress ‘Blue Ice’. Photo: D. Ricigliano

Alternatives to Blue Spruce

If you are looking for a nice evergreen tree for your landscape, consider any of the following alternatives to blue spruce. These have fewer disease problems. Be sure to research the growing requirements (e.g., winter hardiness, etc.) for these trees, to make sure they are appropriate for your location in Maryland.

By Dr. Dave Clement, Principal Agent, University of Maryland Extension, Home & Garden Information Center. 

Have a plant or pest question? University of Maryland Extension’s experts have answers! Send your questions and photos to Ask Extension.

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