Tomato hornworms can grow as large as 5 inches long.
ControlsUse Bacillus thuringiensis (Bt) when caterpillars are small. Hand-pick and destroy large caterpillars. Don't worry -- caterpillars cannot sting with their ″horn.″
*** If you find a caterpillar with what looks like grains of white rice attached to its body, do not remove it. The ″grains″ are the pupae of a parasitic wasp that attacks hornworms. Leave the parasitized caterpillar in the garden so the pupae it carries can turn into more wasps to help control other hornworms. ***