One of the few topics of discussion this Sunday at our Tree Clinic. Caroline Larose from Arborfolia has shared the following:
Here is some information on black knot found on Prunus genus, such as cherry trees, plum and almond trees.
The black knot is caused by a fungus that spreads very easily by wind and rain during the growing season from tree to tree.
Now is a good time to monitor your trees and identify if they are infected or not by this fungus. The first symptoms are a green bump that are found at growing points on the branches and trunk. It will grow for about 2-3 years into a black gall, tar-like of 4-6" big. The fungus will continue to grow inside and outside until it will dry the branch to death.