Problem Identifier Unit Screen//v.w/ RR Template Tomato Hornworm and Tobacco Hornworm


Problem
Fat green or brown worms, up to 5 inches long, with white diagonal side stripes, chew on the leaves. A red or black "horn" projects from the rear end. Black droppings soil the leaves.

Analysis
(Manduca quinquemaculata and M. sexta)

Hornworms feed on the fruit and foliage of eggplants, peppers, and tomatoes. Although there may be only a few worms 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 hatch from eggs laid on the undersides of the leaves, and 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.

Solution
Treat the plants with an insecticide containing pyrethrins, carbaryl, or the biological insecticide Bacillus thuringiensis (Bt). Don't destroy worms covered with white sacs. Let the wasps inside the worms mature, emerge, and infest other hornworms. If practical, handpick unaffected worms.


Related Links
Plant Care for Eggplant
Caterpillars
Insecticides


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