The first symptoms of infection by a tar spot fungus usually show up in mid-June as small, pale yellow spots. The spots enlarge and their yellow color intensifies as the season progresses.

Tar Spots Up Close

On red maple and silver maple, a black spot usually develops in each yellow spot by mid-July to early August. The black spot grows in diameter and thickness until, by late summer, it truly does look like a spot of tar.

What Will Happen To My Landscape?

Tar spot alone is rarely serious enough to threaten the health of trees, but sometimes there can be so many spots that the tree becomes unsightly. Heavy infections can also cause early leaf drop.

What Can I Do About Tar Spots?

The most effective management practice is to rake and destroy leaves in the fall. This will reduce the number of overwintering “spots” which can produce spores the following spring. However, where other infected trees are growing nearby, those leaves should also be raked and destroyed. Also, thinning the tree branches to improve air flow is also recommended. A combination of cultural and chemical control is often required. Most local hardware stores carry fungicides that will help to control tar spot. Because these sprays can cause injury to some plants, read the label thoroughly before using and apply according to the directions. Depending on the severity of the damage, more than one fungicide application may be required for complete control. When combating tar spot its best to think of it as treating allergies, something that will never go away, but having fewer symptoms each year by having regular treatments. Combating tar spot can be a timely and unpleasant weekend task.

How Can Natural Way Help?

Prevention is the key in controlling tar spot. Here at Natural Way we have certified professionals who are used to preventing and controlling diseases like tar spot. Our 6 Point Protection Program will provide several critically timed sprays to the landscape that will help control and prevent tar spot, extend the life of the landscape and minimize overall damage.

Even though tar spot will not generally kill a plant by itself, the plant or tree will become more susceptible to other problems and its appearance will be unsightly.

Tar Spots on Tree

Photo of Tar Spot on maple leaves – credit: Haruta Ovidiu, University of Oradea,