What to Do When a Pumpkin Gets Worms

Identify the Insect

• Before you can properly treat worms in pumpkins, you will need to identify the insect that is producing the worm. The most common insects that attack pumpkins are squash vine borers, striped cucumber beetles and pickleworms. Look for adult and larvae stages of these pests in the pumpkin patch. Adult squash vine borers resemble wasps and are dark-colored with orange spots on the abdomen. Their larvae are cream-colored with brown heads and are about 1 inch long. Striped cucumber beetles are yellow, 1/4-inch-long beetles with three black stripes on their wings. Their larvae are 3/8-inch long and are white with a brown head. Pickleworms are the larvae stage of a small brown and yellow moth that is only active at night. The larvae are yellowish-green worms with brown heads.

Squash Vine Borers

• Squash vine borers deposit their eggs at the base of the plants. Once the eggs hatch and the larvae enter the vines, insecticides will not penetrate the stem and kill them. Use yellow sticky traps to detect the adult borers. If they are active around the pumpkins, spray or dust the pumpkin plants with insecticides containing carbaryl, permethrin, bithinfren or esfenvalerate as the active ingredient, mixed and applied according to the label. Make at least two applications at intervals suggested by the manufacturer. If you can detect where the larvae have entered the stem, make a slight cut at the entry point, then remove and destroy the larvae. Cover the cut section of the vine with 1 inch of soil. The plant will sometimes recover and continue to grow.

Striped Cucumber Beetle

• Striped cucumber beetles feed on emerging leaves, stems and fruits, and larvae feed on parts of the pumpkin plant that contact the soil. The beetle also carries deadly bacterial wilt, which overwinters in their bodies and infects all members of the pumpkin family. You can spray or dust insecticides containing carbaryl or rotenone on the pumpkin plants if cucumber beetles and their larvae are present. Apply sprays made from wettable powders, recommends Ohio State University Extension, since pumpkin leaves are sensitive to liquid concentrates.

Pickleworms

• Pickleworms are often found in pumpkins in the southern parts of the United States. The adult moth lays her eggs on the leaves and blossoms of pumpkins. In a few days, the eggs hatch, and the worms begin feeding on the plant leaves, stems and blossoms. If the pumpkins have formed on the plant, pickleworms will often feed on the rind and interior of the pumpkin. Because the moth is active only at night, the University of Florida Extension recommends covering the pumpkin plants with floating row covers each evening. Remove the covers during the daytime to allow insects to pollinate the blossoms. If pickleworms are already present, dust or spray pumpkin plants with Bacillus thuringiensis, or Bt, an organic insecticide, according to label directions.

Worm Prevention

• To prevent infestation of worms in pumpkins, clean up and destroy all the pumpkin vines immediately after the harvest. Clean debris from the garden after the season, since pests often overwinter in the soil. You should also plant pumpkins in a different location in the garden each year. If pickleworm is a problem in your location, plant pumpkins early in the season, since the adult moth is less active in cooler weather.