Tar Spot on Maples
Don’t let black tar-like spots on the leaves of your maple tree make you fret. Although it’s one of the more noticeable diseases, it’s not detrimental to the vitality of healthy plants.
A European tar spot fungus found its way to North America and has become a common problem on Norway, striped and sycamore maples in parts of the U.S. and Canada. The North American native tar spot fungus is often seen on our native silver and red maples.
The disease is more common in dense plantings and summers following a wet spring. Although the symptoms appear early in the season they become more pronounced and noticeable over time.
The disease-causing fungi survive the winter on the tar spot infected leaves lying on the ground. Rake and destroy the leaves to help reduce the source of infection. Increase success by getting your neighbors to do the same.
A bit more information: Anthracnose is another common problem on maples. This fungal disease causes irregularly shaped brown spots along the leaf veins. Infection usually occurs on younger growth and is prevalent on lower leaves.