Symptoms and Diagnosis Irregular, light brown spots of dead tissue develop along the veins of the leaves. Affected plants may have the appearance of being sun scorched. Sunken red ovals, containing fungal spores, develop on infected twigs of some trees, such as sycamore. Life Cycle Anthracnose fungi overwinter on fallen leaves and twigs that were infected the proceeding year. Infection by the fungi is favored by cool, moist weather in the spring of the year.
Infection occurs on the vulnerable young leaves when there is a film of water on the leaf surface.
Infection is most severe on the lower third of the tree, where the humidity is generally the highest. Integrated Pest Management Strategies 1. Collect and destroy infected leaves as they fall. A source of spores for new infections in the spring are infected leaves and twigs that remain in the vicinity. Prune out dead branches.