Carpenterworm
Prionoxystus robiniae
155 host plants
Last updated
Carpenterworm larvae bore large tunnels through the heartwood of hardwood trees, leaving round exit holes up to a quarter inch wide and accumulations of coarse frass at the base of the trunk. You will notice sap oozing from entry points and sawdust-like debris on bark and around the root flare. Damage develops over several years as larvae tunnel through the wood of oaks, maples, willows, and other broadleaf trees.
Maintain tree vigor through proper irrigation and soil care to enable natural defenses. Probe accessible tunnels with a flexible wire to kill larvae. Inject beneficial nematodes into fresh bore holes and seal the openings. Avoid wounding trees during the adult moth flight season in late spring and summer. Remove severely compromised trees that pose structural hazards.
Quick Reference
Cultural Controls
- Keep trees healthy to enable them to tolerate some damage.
- Prevent injuries which may attract carpenterworm moths to trees.
- Probe tunnels with a sharp wire to kill larvae (when practical).
- Apply beneficial nematodes (Neoaplectana carpocapsae or Steinernema feltiae) into tunnels to kill larvae.
- Fill tunnels with nematodes in water, then plug holes and wait about a week.
- It may be necessary to treat tunnels again if plugged holes are reopened by surviving larvae.