The centers of large spots become grayish tan and the causal fungus produces tiny, black fruiting bodies on the upper surface of the spots. Leaf spot is fairly common but rarely life-threatening to the plant. Rake up and destroy all fallen leaves and spray with thiophanate-methyl. Read and follow all directions on the label. Anthracnose is caused by the fungus Colletotrichum species.
Symptoms consist of small, brownish spots with light-colored centers on the leaves and twigs.
Tiny cracks in the leaf spots indicate fruiting structures of the fungus. Considerable defoliation can result. The disease is a problem during cool, wet springs. Variegated varieties are more susceptible. Rake up and destroy leaves and twigs from infected plants.