Black Knot is back this spring, and Cold Lake residents are being urged to help keep local trees safe.
Black Knot is a fungal disease that affects Prunus tree species, such as Maydays and choke cherries. The fungus causes brown and black knot-like swelling on the branches of the trees, which if left untreated, will eventually kill the tree and potentially spread to others.
Residents are asked to keep watch for Black Knot this spring and summer, and if spotted, to cut off infected branches.
The city has provided some tips on how to deal with Black Knot:
· Prune out the infected branches between late fall and early spring when the plants are dormant and the knots are easier to see
· Remove the infected branches to at least 15-20 cm (6-8 inches) below the knot
· It is best to prune an infected branch further back to a suitable location, such as a healthy collar, rather than leave a stub
· For knots on the trunk or scaffold branches (main branches growing directly from the trunk) that can’t be removed, cut away the diseased material down to good tissue and at least 1 cm (1/2 inch) beyond the edge of the knot
· Sterilize your cutting tools between each cut using bleach to prevent further spread of the disease
· Destroy infected prunings immediately, as they can continue to produce spores for months after being removed
Again this year, the City of Cold Lake will be providing a burn bin at the Cold Lake Transfer Station for residents to dispose of their Black Knot tree clippings.
The city says not to compost these clippings. These branches can be dropped off free of charge and will be disposed of safely by city staff in a controlled burning container.