In the fall, they bore into the sapwood and excavate overwintering cells. In the spring, the larvae pupate and later the adults chew D-shaped holes through the bark and emerge. Tunneling by the larvae often girdles branches, cutting off the flow of sap. This causes the tips of the branches to die back to the point of girdling. Infested trees die from the top downward.
Girdled branches retain dead leaves after they die.
Heavily infested trees should be cut down and destroyed. Chemicals labeled for borers can be used to kill adults and newly hatched borers. Treat the entire tree, especially the upper part, in late May and repeat the treatment twice more at 3-week intervals. Cornell University Press, pg 232 3.