Recently we submitted samples to UofM lab. Diagnosis of needle cast and Rhizosphaera. After reading the information on the fungi, it suggest treatment should start in the spring. Question then is do we wait to treat next spring? Question should we remove brown lower branches?
Scott County Minnesota
If your lower branches are dead, you may remove them. That will help with air circulation. Branches that stay wet for a long period of time are more likely to become infected. The spores are spread usually in the spring but it is possible until early fall. If you wish to treat your tree now you may but then it needs to be treated twice in the spring to protect the new needles. Here is our publication on this disease: http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/spruce-tree-diseases/rhizosphaera-needl...