Squash Vine Borer

These insects are serious pests of squash, cucumber, melon, pumpkin, and gourds. They overwinter in the soil as larvae or pupae. The wasplike moths emerge in late spring/early summer and lay oval, flat brown eggs on the stems and leaf stalks. The eggs hatch in about a week and the white, wrinkled larvae bore into the stem where it feeds, causing the vine to wilt and die. Expect two generations per year.

Control: Rotate planting sites. Till the soil in late winter to expose the overwintering larvae. Plant as early as the weather allows. Insecticides are available, but unless you can time your application precisely, squash vine borers are difficult to control once inside the stem. Cover young plants with a spun-bonded row cover to keep the egg-laying moths out; remove the cover to allow for pollination. If a stem has been attacked--look for an entry hole near the base and some fine, brown sawdust-like frass (insect feces), carefully split the stem lengthwise with a penknife and remove the borers or kill them with a long pin or needle.