May 8, 2019
The fungal disease Cytospora canker is common in Montana and is most damaging on Colorado and Norway spruces. The first indications of Cytospora canker are dying lower branches with bluish-white-colored resin flowing from cankered areas. Upper branches die in subsequent years. Infected inner bark and the cambium tissue directly below the bark are brown, whereas healthy tissues are light-colored. Removal of outer bark slivers just beyond the resin soaking often exposes black pinhead-sized depressions (spore-producing fungal bodies).
Cytospora invades trees through wounds....