Prionoxystus robiniae
Pest description and damage Carpenterworms are the larvae of a large, mottled gray and black moth whose size ranges from 1.75 to 3.0 inches in length. The caterpillars are greenish to pinkish white with a dark head and are one to three inches long when mature. The caterpillars bore into the trunk and main branches of cottonwood, ash, birch, black locust, elm, oak, maple, pear, poplar, willow, locust, and occasionally other fruit trees, shrubs and deciduous trees. Discolored or bleeding limbs, branch dieback, and lumpy or gnarled trunks may be indications of carpenterworm infestation. Typical symptoms of infestation include sawdust-like material (frass) and wood chips mixed with loose webbing on or around infested trees. Trees with severe carpenterworm infestations are susceptible to wind breakage and may need to be removed.
For biology, life history, monitoring and management
See:
Cottonwood (Populus)-Carpenterworm
Management-chemical control
See Table 4 in: