Pest Alert

A More Severe Fungus One fungus in particular is found locally on the native shrub. Mountain Laurel Leaf Blight is caused by the fungus Diaporthe kalmiae (Phomopsis kalmiae). The disease can be distinguished from other leaf spots by the larger, circular, brown lesions that often develop a spotted pattern.

The lesions frequently first appear near the margin or leaf tip, gradually enlarge, merge with other lesions, and result in the death of the entire leaf blade. The fungus may also spread from the leaf through the petiole into the twig, causing twig blight.

Leaf Blight is rarely serious enough to kill plants. We do not recommend treating these plants. The new leaves will often come out nice and the old leaves will eventually fall off.