(Manduca quinquemaculata and M. sexta)
Hornworms feed on the fruit and foliage of tomatoes, peppers, and eggplants. Although only a few worms may be present, each worm consumes large quantities of foliage and causes extensive damage. The large gray or brown adult moth with yellow and white markings emerges from hibernation in late spring, and drinks nectar from petunias and other garden flowers. The worms that hatch from eggs laid on the undersides of the leaves feed for 3 to 4 weeks. Then they crawl into the soil, pupate, and later emerge as adults to repeat the cycle. There is 1 generation a year in the North and 2 to 4 in the South. Some worms may have white sacs that look like puffed rice on their bodies. These sacs are the cocoons of parasitic wasps that feed on and eventually kill the hornworm.
Treat the plants with an insecticide containing carbaryl or with the biological insecticide Bacillus thuringiensis (Bt). But don't destroy worms covered with white sacs. Let the wasps inside the worms mature, emerge, and infest other hornworms. If practical, handpick and destroy unaffected worms.
Plant Care for Tomatoes