Japanese Maple Leaf Spots: Phyllosticta Leaf Spot Diagnosis and Management

A 4-year-old Japanese maple in Wendell, NC shows leaves with holes, dryness, and curling. The owner is concerned about wildlife and pets.

Expert Diagnosis

The damage is caused by Phyllosticta leaf spot, a fungal disease (Phyllosticta minima). It infects late in the growing season, causing minimal damage—mainly premature leaf drop. The disease affects Amur, Japanese, red, and silver maples. Spots are circular, tan with purple-red borders, later developing black fruiting bodies in rings.

Management Options

• Fungicide treatment is rarely necessary due to minimal health impact.
• If desired, apply a labeled fungicide containing mancozeb or chlorothalonil in spring on new leaves.
• Reapply every 14–21 days if rain washes it off.
• Fungicides will not harm wildlife or pets.

Large trees are difficult to spray; the expert considers it not worth the effort.

Japanese Maple Tree