Blue Spuce

Asked June 7, 2017, 8:18 PM EDT

Have a white fungus on the trunk of my Spruce tree which killed the branches from there down. Hoping there is something I can spray on to kill the fungus. I have found a small amount on another tree.

Winona County Minnesota spruce horticulture

1 Response

I can't tell for sure, but most likely you are seeing cytospora canker, a common disease of blue spruce in our area. Read here:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/spruce-tree-diseases/cytospora-canker/i...

This site has some excellent photos:
http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advi...

You will have to aggressively prune it out in order to get ahead of it. This site gives instructions on how to deal with it if it is in the trunk:
http://plantclinic.cornell.edu/factsheets/cytosporacankerfruit.pdf

Cytospora canker is one of several diseases that make blue spruce a poor tree choice for our climate. Since your tree is small and would not be expensive to take out, you might consider that option. You may never get ahead of the cytospora, which will disfigure the tree. And the cytospora will weaken the tree, making it susceptible to the others in the cluster of spruce diseases:
https://www.extension.umn.edu/garden/yard-garden/trees-shrubs/choosing-landscape-evergreens/