Adult beetles are around 3/4 inches long. Their jet-black background is emphasized by vivid yellow bands that run over the thorax and wing covers, with a W-shaped third band on the wings.
The legs are reddish, while the antennae are black and relatively long.
They are similar to the painted hickory borer, except they are active in the fall rather than the spring. Legless, white, robust, and about 1 inch long, full-grown larvae have no legs.
Host plants: This species is only found in black locusts (Robinia pseudoacacia). It is not known to harm other Robinia species or honeylocusts.
Territory:
This borer is found throughout eastern America and Canada
Damage caused by Locust Borer:
Locust borer threats only black locust. Tree limbs become weaker due to locust borer larvae tunneling, leaving them more vulnerable to wind and ice breaking. Tunneling in the trunk may cause trees to grow quicker in those places that have been injured, resulting in knotty swellings. In general, black locust damage may go unnoticed until a considerable number of tree limbs have been broken, and the crowns have begun to weaken, and dieback, or until vast volumes of sawdust-like frass have accumulated at the base of the trunk. The value of the timber for use as fence posts or firewood decreases over time due to repeated infestations.
Life history and Habits:
Adults are most active in late summer and early fall, from late August to October. During the morning hours, they are frequently seen eating on the pollen of goldenrod blooms. They can be spotted seeking egg-laying places on the trunks of black locust trees later in the day, sometimes far after dusk. Eggs are often laid in rough bark cracks and around wounds on live tree trunks. Newly born larvae tunnel into the inner bark and build little hibernation chambers to spend the winter there. When the leaf buds begin to expand in the spring, activity resumes. Oozing sap can be visible around larval entrance pores in the trunk at this stage. The larvae quickly bore into the wood, where they fed until they matured in mid-July. As the larva develops, it expands its tunnel to the outside, via which it pushes its granular frass to the outside and finally emerges as an adult. Every year, there is a new generation.
