Limbs or entire trees, especially young trees, may be killed by these borers. Most flatheaded borers do not attack vigorous plants. Larvae bore tunnels beneath the bark and sometimes into the wood. Tunnels are often winding and filled with frass. A typical example is the flatheaded apple tree borer.
Most adults are medium to large, elongate, cylindrical beetles that are often brightly colored.
Larvae bore beneath the bark and sometimes into the wood on tree limbs, trunks, and main roots. Larvae are generally creamy white, elongate, and cylindrical. Dogwood twig borer. Three black spots, arranged in a triangle is visible on the top of the thorax. The larva, which is yellowish and legless, bores into the twig.