Symptoms and Damage Adults feed on the leaves and bark of fine branches causing considerable damage. They prefer to attack the shoots of host trees causing the young shoots to wither and die. The female chews round or lip-shaped grooves in the bark of the trunk or large branches into which she lays a single egg. Young larvae feed in the green inner bark and cause scoring of the cambial layer. Mature larvae bore into the xylem of the tree, and create large, winding galleries in the inner wood, eventually killing the host.
Infested trees are also prone to secondary attack from other insects and diseases.
Yellowing foliage, pre-mature leaf drop, and bleeding of sap from egg laying sites are other indicators that the insect is present. Adults feed on the leaves and bark of young branches, causing considerable damage. The adults begin emerging in May and populations peak in early July. They are active until October. Sap, which is often frothy, leaking from egg-laying sites often attracts bees, wasps, yellow jackets or butterflies.