Red-necked Cane Borer
The adult red-necked cane borers, Agrilus ruticollis (Fabricius), can be identified by the reddish section (thorax) behind their head; the rest of the body is black. Characteristic injury caused by these borers is a swelling of the cane that can be from 1/4 to 3 inches long and can occur at any place on the cane. The cane usually is weakened or breaks off at the swelling.
The adult beetles are present from late May until early August and range from Canada to the gulf states and as far west as Minnesota. On sunny days, they can be seen feeding on the bark of new growth. The creamy-white larvae, approximately 3/4 inch long, have a pair of darkly colored forceps-like prongs on the abdomen. The young larvae bore into the sapwood of the current year's growth (primocane), make winding tunnels around the stem that split the bark, and finally work through the hardwood and into the pith. Infested canes are weakened and often die.
This insect usually is controlled by cutting out and removing infested canes from late fall to early spring. Prebloom and/or postharvest sprays of broad-spectrum insecticide may be considered when heavy populations are present.