Squash vine borer is the bane of the backyard vegetable gardener. This insect can cause squash plants to suddenly wilt and be weakened or killed, unless the gardener takes steps to prevent it. The borer is a fat, grublike caterpillar, with a white wrinkled body and brown head that gets into and girdles plant stems, preventing the movement of water and nutrients. It feeds inside the plant for four to six weeks, reaching about 1 inch in length. It then exits the stem and crawls into the soil to pupate.

In addition to squash, the borer also attacks pumpkins and gourds. Hubbard squash is preferred over other hosts, and butternut is less susceptible than other squashes. There are several pest management options for squash vine borer. One is to handpick the adults before they lay eggs at the base of stems; they emerge in June and are active for about a month. Adults look somewhat like a wasp. The body is black with orange-red markings. Front wings are metallic green and the hind wings are clear. The hind legs have orange and black hairs. They rest on the plant's leaves in the evening and early morning.

Eggs are dull red, about 1 millimeter long, and are laid on the main stem near the ground, on leafstalks, or on the undersides of leaves. Eggs can also be handpicked and destroyed. Some gardeners have successfully created a barrier on the stems by wrapping them with strips of old nylon stockings to prevent egg laying or by using row covers to exclude the adults from the plants. Others have planted squash seed about July 1 to avoid this pest altogether, though they harvest their crop a bit later.

Standard insecticides can also be used, but timing is critical. Apply when vines begin to run and repeat every seven to 10 days for three to five weeks, directing the spray or dust at the plant's crown and runners. Contact y our local Cooperative Extension Service office for specific pesticide recommendations. Read and follow all label directions.