Native to the Allegheny Mountains from Pennsylvania to Georgia, this nitrogen-fixing leguminous tree was quickly introduced wherever the colonists and traders went for its extremely durable wood and ease of propagation. Many older farm sites in Vermont and the Northeast can be identified by the groves of old black locust trees. In late summer, the trees appear as if scorched by fire. Reported from Albany and Rensalaer County, New York, by the turn of the century, it was not known from Vermont nor northern New York by 1970, but had been observed in Cheshire and Grafton Counties in New Hampshire along the Connecticut River. The LLm has been very damaging to black locust in Chittenden County for well over two decades, beginning with the plantings along I-89 at the Richmond Interchange.
Significant damage is only to the black locust.
In August, the newly emerged overwintering adults feed on the upper leaf surfaces only, skeletonizing the leaves. The very small, pin-hole feeding holes found at this time are from a very small black weevil, Apion nigrum Herbst, which breeds in black locust seed pods. Complete defoliation, as reported in the Lake States and further south, has not been observed in Vermont. The remainder of the wings and the dorsum of the thorax are an orange red. The mature larva is somewhat flattened, yellowish white, slightly longer than the adult, with the head, thoracic and anal shields, and legs dark black.