Causes & Symptoms
Anthracnose is a fungal disease that can affect multiple species of trees, most notably Maple, Oak and Ash. Cool, wet spring weather are needed for this fungus to thrive. If these conditions occur, it is fairly common to see species of oak, maple and ash trees showing symptoms that include brown spots on leaves, curling or distorting of leaves and leaf drop.
Typically, Anthracnose is most prevalent on the lower, inner branches where humidity levels are generally higher. On oak trees, this characteristic helps differentiate Anthracnose symptoms from those of Oak Wilt, a much more serious, systemic fungal disease. These symptoms typically show up in late spring or early summer and can cause defoliation of a tree, which creates a bit of concern for tree owners. However, the leaves typically drop early enough in the season that a healthy tree will 'push out' a second flush of growth.