Examine dead twigs near the ends of branches for pimple-like fruiting structures peppering discolored, slightly sunken bark areas. Although wet weather tends to favor this disease, temperature is the most important factor. If daily temperatures average above 60 F at bud break, anthracnose is usually not severe. The fungus survives the winter dormant primarily in cankers on infected branches and twigs. To a small extent, the fungus also survives in fallen leaves.
Wind carries the fungal spores from the cankers to developing leaf and twig tissue.
Infected young twigs are girdled and killed. The fungus forms new spores on the infected leaves and twigs. These spores are then blown or splashed to nearby foliage where they germinate, penetrate and cause additional spots if weather conditions are favorable. Infected leaves shrivel and fall. Rake and destroy fallen leaves around susceptible trees that have branches close to the ground.