Japanese Maple Diseases

The Japanese Maple tree is a medium size tree that can be grown as a tree, accent plant, bonsai, or border shrub. Native to Japan, China, and Korea, this tree, depending on its species, can range in height from 6 to 50 feet. The tree prefers warmer climates, moist soil and neutral acidic levels. Though the tree can be easily cultivated, it is susceptible to some disease.

Tar Spot

Tar Spot is a fungal disease that attacks the leaves of the Japanese maple. The fungus rests on fallen leaves, surviving through the winter. In early spring, the fungal spores are blown onto the newly forming leaves, causing the tree's infection. An infected maple will initially show yellowing spots on its leaves, which turn black as the summer progresses. Though the disease creates an unsightly tree, it is not harmful to it and can be treated with a fungicide.


Anthracnose is a fungal disease that attacks the foliage and tissue of the Japanese maple tree. Also common in oak trees, the disease generally attacks when the climate is warm and rainy. The infected tree will show signs of defoliation, brown lesions, leaf flight and fungal fruit bodies underneath the leaf's surface. This fungus is relatively harmless to the tree but requires diligent action to eliminate. A combination of leaf collection, fertilization, irrigation and fungicidal applications will correct this disease.

Verticillium Wilt

Verticillium wilt, also known as maple wilt, is a common and deadly maple tree disease. This fungal disease originates in the soil surrounding the tree and slowly attacks the tree's internal tissue. An infected tree will not begin to show signs until the disease has passed through its system. Maple wilt causes dieback, wilting, leaf drop and eventually death. While some trees successfully recover from the disease, it is hard to control and eliminate. Horticultural specialist can assist with fighting this disease.

Shoestring Root Rot

Shoestring root rot is a fungal disease that is caused by Armillaria, a group of hard to identify fungi. While the disease attacks the roots of the tree, the Japanese maple will show signs above the ground. These symptoms include yellowing and browning of foliage, growth stunting, and leaf drop. The disease also shows signs just underneath the bark of the tree. These signs includes black, string-like strands, and white, felt-like fungal growth which can be seen when the bark is peeled back from the tree. No cure exists for this disease and infected trees should be uprooted and destroyed.

Keywords: Maple Wilt, Japanese mape diseases, anthracnose, shoestring root rot, maple wilt

About this Author

Writing professionally since 2004, Charmayne Smith focuses on corporate materials such as training manuals, business plans, grant applications and technical manuals. Smith's articles have appeared in the "Houston Chronicle" and on various websites, drawing on her extensive experience in corporate management and property/casualty insurance.