Norway Spruce Rhizosphaera needle cast
I have checked numerous times on a white board to try & find spider mites, but have seen no insects. I cannot see any fungus spots on the needles, however, I think it is needle cast. The spruce is planted in a shady damp place. It is in a line with several other spruces which are unaffected. If I am right, should I treat it or remove it.
Grand Traverse County Michigan
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It does look like needlecast. Some individual trees tend to be more affected than others. Norway spruce is not usually affected, but with the wet spring and fall weather I've seen it on Norway spruce here in the Roscommon area.
Depending on how affected the tree is, and how large it is, I would remove if possible. Possibly trimming the tree up a few feet might also help as this increases airflow and decreases the damp conditions under which needlecast thrives.
If the tree is small enough, you can treat the new growth to prevent it from being infected with needlecast.
I hope this gave you a bit more information. Feel free to respond with additional questions, or call me on my cell to discuss further. 989-390-0317.
Thanks so much, Julie, for such a speedy reply & for the info. Much appreciated!