What is eating the leaves of our Maple trees and turning the leaves red?
Our Maple trees have some holes in the leaves that look like something is eating them. They also have red and black raised dots on the leaves. At the tips of some of the branches, the leaves look like they are starting to turn reddish as if fall foliage was starting! Should we be concerned?
There are numerous pests (notably mites) that can cause foliage holes and raised galls on maple leaves. As long as the tree isn’t being defoliated on a large scale and appears otherwise healthy, this is typically cosmetic damage and no serious threat to the tree. If the problem becomes widespread or the tree begins to deteriorate, we would want to have you scout for pests and submit some samples to the appropriate UMaine Extension laboratory.
Maple tree leaves changing color early is often a sign of environmental stress. Depletion of soil nutrition, over- or under-watering, planting depth, and temperature can all play into this. Have you had the soil tested in the last few years?