The white, leg less larvae feed gregariously on the inner bark and several gallery colonies may completely girdle the tree. When the larva matures, it constructs a pupal cell between the bark and the sapwood. The pupation period, during which the larvae are transforming to adult beetles, is about 10-14 days in duration. The adults then emerge through the bark and the cycle is repeated. The length of the cycle is determined by the prevailing temperatures, and usually takes from 3 to 4 months to complete.
Development is slowed during the cooler months.
In the Long Island area, emergence of beetles can be expected from mid-April and will occur throughout the summer because of the overlapping of broods. When insect populations are high, healthy trees may be attacked. The site of attack is usually the lower 6 feet of the trunk, but as stated earlier, main roots are sites also. In cases where a large number of invasions take place, accumulations of hardened, granular pitch may be noticed on the ground at the base of the tree. Under the bark, large cavities excavated by the larvae may extend from the egg galleries downward into the larger roots.