I have a Canadian Cherry Tree which has been infected with black knot for the past few years. The tree is approximately 20 feet tall and about nine inches in diameter. For the past two years, I have been trimming the infected branches, but to no avail. At this point, what are my options?
Continue to prune out infected areas. Fungicide treatments applied in the early spring have had little effect on control. Prune now where you see the early stages and ones you have missed a little latter. It is a tough disease to control, though.
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