Knowledgebase
Canadian Cherry - gall #929707
Asked April 26, 2026, 8:08 PM EDT
Franklin County Ohio
Expert Response
I assume that it is the black knot pathogen causing the issue. You need to continue to prune out affected branches, but you can also spray a protective fungicide to reduce spread of the pathogen. Any fungicide containing chlorothalonil or captan will be effective. Spray every 10 days now through mid June.