Wednesday, September 17, 2008

Blue Spruce Problem

Everyone seems to like blue spruce, and nobody is happy when they notice Rhizosphaera needle cast attacking there favorite evergreen. This fungal disease attacks tender young needles in the spring, and preventative treatment must happen then if it is to be effective.
Rhizosphaera starts low on the north side of spruce trees, and moves upward and outward over a period of several years. Homeowners need to spray a fungicide on the trees early in the growing season to keep this disease from infecting new growth. Removal of dead and infected branches is a good idea, too. This tree was sprayed aggressively for several years, but the disease has won, and it does not have enough live crown to recover now. The good news is that a Douglas-fir nearby seems to have no problem living in Illinois.
Don't depend too heavily on one species in your landscape plantings, and try not to take it too hard when a tree doesn't work out.

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