Both DB and ABB treat burr knots as wounds, with females ovipositing at such sites. Reddish frass at burr knots is a sign of infestation. While the burr knots themselves disrupt sap flow, girdling is enhanced once larvae are present. Furthermore, once established, feeding may extend beyond the burr knot into healthy tissue. Chronic infestations will cause a decline in vigor, yield, and may rarely kill the tree.
Infestation produces rough bark that is conducive to further infestation.
Infestations may occur in recently top-worked trees, females treating these as wounds. Females are attracted to dark grafting wax and tape. Traps should be placed in mid-April, and monitored through July. Trapping in Virginia has shown that lilac borer traps are more effective at trapping DB than are DB traps. Antennae are red with black on the dorsal side.