Squash Vine Borer: The Pest That Kills a Healthy Vine in a Week
The wasp-like moth that lays eggs on squash stems in mid-summer; the larva burrows in and collapses the vine. Catch it early or lose the plant.
Squash vine borer is the single most destructive pest of summer squash, pumpkin, and gourd in the eastern half of North America. Healthy 4-foot vines wilt and collapse over 48 hours mid-summer because the larvae have hollowed out the stem from inside. The adult is a wasp-mimic moth — orange and black, day-flying — not a wasp. The damage is done by the cream-colored larva inside the stem.
Symptoms & ID
Symptoms + identification
Earliest sign: piles of yellow-orange sawdust-like frass at the base of squash stems where they enter the soil. Look for it daily from late June through mid-August. Later: sudden wilting of leaves and stems despite damp soil — the vascular tissue inside the stem has been severed by the larva's tunneling. Cut open a wilted stem near soil level and you'll find a 1-inch cream caterpillar with a brown head.