- adults: female wingspan ~ 3 inches, length is 1 3/4 inches; males smaller
- adults: mottled white, gray and black; blend with bark
- larvae: up to 3 inches long; white to pink; brown head capsule; black dots on abdomen
- pupae: skins are dark brown with a double row of spines
- eggs: laid in sticky masses
Host Plants, Diet & Damage
- ash, aspen, elm, birch, black locust, oak, cottonwood maple and willow; poplar favored
- larvae feed on sapwood but primarily in the heartwood
- larval galleries can extend 6-10 inches within the heartwood and are 1/2 inch in diameter
- boring activity weakens branches and stems
- bark can become disfigured and scarred
- frass and pupal skins may be evident in exit holes
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae in the wood
- adults emerge mid-May through July.
- egg masses are laid on tree bark, usually near wounds
- larvae spend most of their time in the heartwood
- one generation every 3 to 4 years
- larvae are the damaging stage
- Keep trees healthy with proper cultural practices.
- Avoid mechanical injury to trees.
- Monitor trees for irregularly shaped holes with expelled frass or pupal skins.
- Nematodes (Steinernema carpocapsae or feltiae) may be sprayed into holes to kill larvae within galleries.
- Apply an insecticide (carbamate; pyrethroid) to the bark in mid-May prior to egg laying.
For more information, see our Carpenterworm fact sheet.