Description: Tobacco hornworm and tomato hornworm are similar in all stages of development. While both species of caterpillars have a large horn on the posterior end of the body, tobacco hornworm has 7 diagonal stripes on each side of the body; tomato hornworm has 8 chevron-shaped stripes. Adult tobacco hornworms are slate brown compared to the ash-gray color of tomato hornworms.
Damage:
Hornworm larvae feed on blossoms, leaves, and fruit. They can extensively defoliate plants and scar fruit. They are rarely a problem in the warmer interior valleys unless natural enemies are disrupted.
Life cycle:
Hornworms overwinter as pupae in the soil. Moths emerge in early June through August. At night, eggs are deposited on the underside of leaves at 1 to 5 eggs per plant visit (may oviposit up to 2,000 eggs total). Larvae emerge 4 days later and develop in 3 weeks as pupae. Heavy egg deposition is common in August and early September due to a peak in overwintering moth emergence along with that of a second (or possibly third) brood.
