What can be done about unsightly black spots on the leaves of a red maple...

Asked April 14, 2014, 1:50 AM EDT

What can be done about unsightly black spots on the leaves of a red maple tree? For the last two years, my brother's tree has looked ghastly.

Ottawa County Michigan

1 Response

Based solely on your description (no photo available), it sounds as though your brother's tree is affected by tar spot fungus. If so, the condition is certainly unsightly but does not do any long-term damage to the tree. The most effective solution is to ensure that all leaves of affected trees are raked up immediately and disposed of so that tar spots do not survive in the vicinity of the tree to release spores and begin their cycle of infection again in the spring. Because this is an airborne disease, even if you carefully rake and dispose of all affected leaves, your trees may become infected again by other maples in the area (neighborhood) infected with tar spot. For more detailed information and pictures of diseased leaves, please see this fact sheet: Tar Spots of Maple.

If the photos in that article do not look like the affected leaves that you are writing about, please write back with either a photo or more detailed description of the leaf damage, and we will do our best to assist you with the problem.