Carpenterworm Moth

Pest Description

• 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

IPM Recommendations

• 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.