Hi, I have a (about) 10 years old Plum tree (sorry not sure which type) with a bad case of black knot in the Sunset area in Vancouver. Aside from cutting the whole tree down what are my options? thanks for your help
Black knot is a fungal disease, and spreads (within the tree and to other trees) by spores. Treatment consists of cutting off affected branches 3-4 inches below the "knot", including all the current years immature knots which can be harder to spot. Prevention is the usual run of fungal products from dormant oils to systemics, but in my experience (2 trees) the oils just slowed it down. The trees were removed after 2 or 3 years. I don't know if there is a specific systemic for black knot. All the cuttings must be burned as they remain infectious. How bad is "bad case"? Imagine the tree minus all the affected parts and decide if you still want it. Also consider any other susceptable trees (prunus spp) that may be at risk. Ralph
:) you could try to push it over ..... or burn it down..... sorry, couldnt help but throw a couple of one liners in. It depends on what "bad" means. pruning well below an affected area is important, look for wood staining, attempt at CODIT, this will give you an idea of how far damage has progressed in the tree.
