Fact Sheet

Maple Tar Spot

Have you noticed black spots on maple leaves?

It may be from a condition called maple tar spot. This is caused by wind-borne spores traveling from fallen leaf litter to newly
developing leaf tissue.

The Problem

Three species of Rhytisma can cause different lesions that begin as small light green/yellow spots on leaves that gradually increase in size and darken to dark brown/black. By early fall they can become very obvious.

Symptoms and signs include:

Small light green/yellow spots in late spring
Larger dark brown/black spots in fall

Co-occurring issues or look-alike symptoms:
Eriophyid mites, SGRs

The Vineland Prescription

For maple tar spot treatment, remove and dispose infected leaf litter in the fall to reduce spore pressure the following spring.

The Prognosis

Trees almost never show any signs of stress even after severe infections, so treatment isn’t needed. They will recover the following year.

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