Squash vines suddenly wilt. Holes in the stems are filled with a green or tan sawdustlike material, which spills out of the holes. Fat, white worms up to an inch long are found in the affected vines when the stems are slit open lengthwise with a knife.
Slit the affected stems with a knife and destroy the borer. If the plant has not died, cover the damaged portion of the stem with soil, keeping the soil moist to encourage new roots to grow. The vine may recover. Destroy dead plants in the fall. The following year, treat plants with an insecticide labeled for these pests, following label directions. Adults can be kept from laying eggs with row covers.