Tar spot on maple trees is hard to miss. When it appears, yellow-green spots form on the upper surface of the leaves, gradually turning black. These spots resemble tar.
Should I cut down my tree?
The disease rarely poses a serious threat to the health of the tree. It is mostly an aesthetic issue. Leaves may fall prematurely. Once on the ground, the fungus continues to develop until spring. The fungal spores are then dispersed by wind and rain, infecting new leaves.
Can my neighbor’s tree transmit the disease to mine?
The fungal spores spread easily through wind and water, making your tree vulnerable to infection from a neighboring tree. However, tar spot does not affect all tree species. In urban areas, this disease is primarily found on silver maple and Norway maple but also on red maple and sugar maple. If your tree is not a maple, there is no reason to worry.
How can I get rid of these spots on my tree?
It is recommended to collect fallen leaves and destroy them immediately. This measure helps reduce the spread and reinfection in the following spring. It may take a few years to completely eliminate the disease, provided there is no risk of infection from nearby trees.
Image : Ressources naturelles Canada