Cottonwood, poplars, willows, etc.
The adult cottonwood borer is a large, longhorned beetle, about 1 1/2 inches long, with a black body color, that is obscured by patches and cross stripes of fine pure white hairs that surround black, hairless areas. There is a strong spine on each side of the thorax and the antennae are as long as the body. Adults begin to emerge in late May or early June in Oklahoma and feed on the tender shoots of young trees. The cottonwood borer breeds in the bases and roots of living cottonwood, poplars, and willows. Eggs are deposited at the base on the tree bark, and upon hatching, the larvae mine downward in the inner bark, penetrating into the wood. Most larvae feed below the soil line. Cottonwood borers lay eggs in tree trunks at the soil surface in July or August. Larvae live for 2 or 3 years in the trees.
Most damage is caused by the larvae on young trees, that may be hollowed, partially severed, or girdled at or slightly below the root collar, causing breakage. Damage of these insects is often overlooked during summer months because the immature borers (larvae) feed in tunnels constructed in twigs, shoots, branches, or trunks. Damage has been greatest in nurseries, and young plantations. Generally, plants lacking vigor are more susceptible to borer attack than are vigorous, healthy trees and shrubs.
Best control is to utilize good cultural practices to maintain a vigorous, healthy stand.