Thousands of Calgary trees are being infected by an airborne fungus that is known as black knot. When the fungus attacks the trees it looks like there is black coal on the trunk, branches or twigs of the trees. Especially prone to this fungus are Mayday and Schubert Chokecherry trees. These are trees that are commonly found in Calgary neighbourhoods and this year they are getting hit hard.
While this black knot fungus has been around Calgary for many years, the last two springs have been especially severe. Discovery Ridge has lost about 50 trees so far.
Although it isn't usually fatal for the trees, black knot can kill the branches. When the tar-like substance wraps around the branches, nutrients have a hard time passing through. In Discovery Ridge, the fungus was extremely severe this year, which led to the tree loss. Cougar Ridge and West Springs are also experiencing a large black knot infestation.
This fungus can travel from one tree to the next so it's very important that all residents take a look at their trees and address the problem. If your tree doesn't have this fungus growing on it but your neighbour's does, a strong downwind could send the fungus to your tree.
Experts are advising residents to look for the black knot on their trees. If any is found, they are suggesting that you remove the branches at least 6-8 inches below the area that has been affected. You should also disinfect any of the pruning tools that you use so that the disease doesn't spread from one branch to another or to another tree.
Once the branch has been removed it should either be burned or buried. It can also be sent to a landfill to be disposed of. If you'd like to see a video outlining how to deal with this fungus you can visit the www.cbc.ca website.