Anthracnose of Japanese Maple

Disease Information


COMMENTS on disease

Anthracnose is a fungal disease that tends to attack plants in the spring when the weather is cool and wet, primarily on leaves and twigs. The fungi overwinter in dead twigs and fallen leaves. Cool, rainy weather creates perfect conditions for the spores to spread. Dry and hot weather stop the progression of the disease.

Symptoms and damage

Anthracnose fungus infects many deciduous and evergreen trees and shrubs, as well as fruits, vegetables and grass. Anthracnose is noticeable along the leaves and the veins as small lesions. These dark, sunken lesions may also be found on stems, flowers and fruits.

In order to distinguish between anthracnose and other leaf spot diseases, you should carefully examine the undersides of leaves for a number of small tan to brown dots, about the size of a pin head. If you are unsure about diagnosing anthracnose, consult your local Cooperative Extension office for assistance and additional anthracnose disease info.


Anthracnose control begins with practicing good sanitation. Picking up and disposing of all diseased plant parts, including twigs and leaves, from the ground or from around the plant is important. This keeps the fungus from overwintering near the plant.

Proper pruning techniques to rid trees and plants of old and dead wood also helps with prevention of anthracnose fungus.

Keeping plants healthy by providing proper light, water and fertilizer will strengthen the plant`s ability to ward off a fungus attack. Stressed trees and plants have a difficult time recovering from anthracnose fungus.

Chemical treatment is rarely used except when the disease involves newly transplanted plants or continual defoliation.


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