This disease rarely requires fungicide treatment. The London plane tree is less susceptible, but there is much variability in its susceptibility or resistance to anthracnose. The Oriental sycamore, Platanus orientalis is resistant. This anthracnose looks different from sycamore anthracnose. On ash, infected leaves have water-soaked spots that enlarge rapidly.
Young lesions are greenish-brown to dark brown.
You may notice it now by finding the infected leaves on the ground. Later infections on leaves approaching full size produce distorted leaves with tan blotches. Some defoliation can occur on the lower branches, but overall the disease usually does not seriously affect the health of the tree. It can damage the tree aesthetically. What's Hot Honeylocust plant bugs have hatched and immature plant bugs are actively sucking juices from newly opening leaves.