Oak anthracnose is caused by the fungal pathogen Apiognomonia errabunda. In Iowa, cool wet spring conditions can lead to anthracnose infection in trees. Anthracnose causes browning of the edges and veins of leaves. In severe infections, leaf drop may occur. The disease normally only causes minor damage to oak trees. Mature trees tend to defend themselves against major damage caused by the fungus. The disease usually eases by the middle of summer because of the weather becoming warm and dry. In some instances, the disease can return in the cool autumn weather and then subsequently over winters. In the spring, the disease returns due to resting structures and the cycle repeats.
To help manage the disease, rake and remove fallen leaves, consistently prune to allow air flow throughout the canopy, mulch, and water during drought.
The Tree Doctor can apply a fungicide to assist with the management of the disease.