Squash Vine Borer

Don't let these moth larvae get the best of your squash plants.

July 25, 2012

Melittia cucurbitae


  • Adults: narrowwinged, olive-brown, 1- to 1 1/2-inch moths, with fringed hind legs, clear hind wings, and red abdomens with black rings.
  • Larvae: white with brown heads. Found throughout the United States and Canada east of the Rocky Mountains and south to Mexico.

Larvae bore into vines of squash, pumpkins, cucumbers, melons, and gourds. They chew the inner tissue near the base, causing vines to wilt suddenly; girdled vines rot and die.

Life Cycle
Larvae or pupae overwinter in the soil. Adults emerge in spring and lay eggs on stems and leaf stalks near the base of the plant. Newly hatched larvae bore into vine stems, causing sudden wilting and death of stems. Larvae feed for up to 6 weeks, then pupate in the soil. One to two generations per season.

Early in the growing season, cover vines with floating row cover; uncover later for pollinators or hand-pollinate. At times when moths are active, check stem bases and destroy any egg clusters that you find. To save attacked vines, slit infested stems and remove borers, or inject vines with BTK; after treating the vines, heap soil over the treated areas to induce rooting.

Learn More: How to Control Squash Bugs

Moth: Rob Cardillo
Larva: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org