The adult beetles have hard shells with a metallic lustre. The heads of the larvae are expanded and flattened. Like the roundheaded borers, these insects are found most commonly in unhealthy trees previously weakened by some other factor. This insect, the bronze birch borer, seeks out birch trees already in poor condition, then lays its eggs in bark crevices or near recent wounds. Spiral swellings hide their winding feeding tunnels under the bark.
Infested trees have sparse foliage and eventually suffer dieback in the upper crown.
Wood-chewing caterpillars make up the third and most important group of borers. When mature, these borers become clear-winged moths which often resemble wasps. Early external symptoms of attack by the peach tree borer are a mass of gum and brown frass at the base of the trunk. A few strokes with an axe will expose the white caterpillars chewing away at the inner bark and sapwood. Peach, plum, and cherry are also attacked at the larger branch forks by a second moth borer, the lesser peach tree borer.