In their larval stage, numerous types of beetles and some clear wing moths tunnel beneath bark or bore into live wood. Some borers tunnel deep into a branch, making it weak enough to snap in a storm; others tunnel just below the bark, girdling a tree. In many cases, a pest’s tunneling pattern is distinctive enough to provide positive identification. Borers tend to attack trees stressed by poor growing conditions or wounds. If you see holes bordered with sawdust, excrement, or sap, you probably have an infestation on your hands. Some species attack below the soil line; in these cases, the evidence may be at the base of the tree.
Borers and Bark Beetles
