There are large, green caterpillars on my tomato plants. What should I do?
The large, green caterpillars are probably tomato hornworms. Tomato hornworms are bright green, up to 4 to 5 inches long, and have red or black, horn-like projections on their rear ends. After feeding, hornworms move to the soil where they pupate and spend the winter. The following summer the pupae transform into five-spotted hawk moths and start the cycle over.
Tomato hornworms feed on the leaves and fruit of tomatoes and other vegetables including eggplant, potatoes, and peppers. They can quickly defoliate portions of the plant and heavily damage the fruit.
Often the best control option for home gardeners is to pick the caterpillars off by hand and destroy them. Another control option is to use a biological insecticide, such as Bacillus thuringiensis (Bt), or a synthetic home garden insecticide. As always, carefully read and follow label directions when using pesticides.