Cerambycidae, Megacyllene robiniae Plants Attacked Black locust Description of Damage Larvae tunnel in trunk and larger branches of live trees. Most damaging on younger trees during dry seasons. They attack healthy young trees boring into the heart and sapwood of stems and branches. Young larvae feeding in the spring cause bleeding at the site of the injury.
Wet spots are present on the bark.
Identification Adult overall color is black with yellow markings. Most characteristic mark is the W-shaped yellow mark on the first pair of wings. Adults prominent in fall feeding on goldenrod pollen. Life History Very small larvae pass the winter in the inner bark of the host. In early spring they begin development moving into the sap and heart woods.