Fresh sawdust-like borings are usually present on the bark near active borer sites. In young trees, the crown is attacked, resulting in wilting and die-back. Larva change to pupa during spring and adults begin to emerge by late May. Adults are most abundant in June though some emerge throughout the remainder of the summer months. Adults are clear-winged moths that are active during daylight hours. They have blue-black bodies with a yellow stripe on the second and fourth segments of their abdomen.
Legs are also yellow banded.
Wings are narrow and transparent. Female moths lay eggs on smooth or rough bark. On older trees, they lay eggs in scars and rough areas of bark on the trunk and larger branches. Caterpillars hatch in 8 to 10 days and wander around aimlessly until an opening in the bark is found. These free-moving larvae are unable to chew their way through bark, so they seek an opening to gain entry to the cambium.