Conifers Disorder: Cytospora Canker

What is Cytospora Canker?

In Wisconsin Cytospora Canker damages varieties of Colorado
Blue Spruce more frequently and severely than any other species. However, it also affects Norway Spruce and, less commonly, other Spruces and Douglas Fir.

What are the symptoms and effects of Cytospora Canker?

Symptoms of Cytospora Canker usually do not appear until trees are about 15 years old and at least 20 feet high. Ordinarily, damage appears first on lower branches of the tree, but occasionally it appears on a single branch higher in the tree. Needles on affected branches turn purplish, then become brown as they die. The needles eventually fall off, leaving bare branches and twigs.

How do you control Cytospora Canker? 

The best way to control Cytospora Canker is to prevent it. Because stress appears to enhance the development of this disease, measures to improve tree vigor should help prevent Cytospora Canker. Irrigation during periods of drought is especially important. Practices that encourage healthy root development will also reduce stress. Fertilization to encourage root growth may help prevent canker development.