Cottonwood borers are huge, long-horned insects 1 to 1 1/4 inches in length. They’re black with white cross stripes caused by thick growths of white hairs. Their antennas, which are black and segmented, are nearly as long as their bodies.
Adults emerge in late spring and early summer. They feed on new, sensitive tree shoots and lay eggs in apertures dug into the bark below the ground line at tree bases.
The larvae dig into the base and roots of the trees, pushing off sawdust-like frass at the places of the entrance, and the eggs hatch in 10 to 14 days.
The larvae are cream-colored and grow 1 1/4 to 1 1/2 inches long. The larvae are cream-colored and reach 1 1/4 to 1 1/2 inches in length.
Host plants:
Cottonwood, poplars, and, on rare occasions, willows are host trees. Throughout its distribution, eastern cottonwood is the primary host tree.
Territory:
The insect is found across the eastern and midwestern United States. However, it is most widespread in the Great Plains from Texas to South Dakota and throughout the Mississippi River Valley.
Damage caused by Cottonwood Borer:
Cottonwood borer infects trees of all sizes. Cottonwood borers can infest nursery stock, causing young trees to die and wilt, or, if the young trees survive, they frequently break at the root collar when handled. Damage to elder trees might be difficult to identify until the soil is removed to expose the root collar and top roots. The larvae dig into afflicted trees’ heartwood. Infested trees in plantations are frequently plagued with larvae, yet they seldom die due to the damage. During heavy wind, severely afflicted trees may break at the base.
Life history and Habits:
Adults emerge in late spring (late May or early June in Oklahoma) and feed on new tree vulnerable shoots. During the summer, mating and egg-laying take place over a long time. To oviposit, the female scrapes away the dirt near the tree’s base, cuts a crevice in the bark and lays one or more eggs. The considerably bigger larvae spend the second winter in enormous tunnels near the tree’s base. Pupation happens in the second spring gallery, and the full life cycle lasts two years. To escape, the new adult bites through the pupal chamber and digs its way to the earth’s surface.
