Pest monitoring Treat hornworms only if they are causing extensive foliage damage, or if they are feeding on fruits. The females begin to deposit eggs on the tomato plants for the next brood of hornworms. The moths emerge from the soil in the spring and mate. The hornworm remains in the pupal stage in the soil all winter until the soil begins to warm in the spring. The full grown larvae burrow into the soil, where they transform into the pupal stage. The larvae pass through five or six stages before reaching full growth in 3 to 4 weeks. They are rarely a problem in the warmer interior climates unless natural enemies are disrupted.īiology and life history In late spring, the adult moth lays eggs on the underside of tomato leaves. At high populations, they can defoliate plants extensively and scar the fruit. Hornworms feed on blossoms, leaves, and fruit. Eggs are light green or yellow turning white at maturity. The adult is a large mouse-brown moth with narrow wings and a wingspan of up to 5 inches. Pupae are brown or reddish brown and up to 2.25 inches long. Pest description and crop damage The tomato hornworm larvae is over 3 inches long when full grown, green, with eight chevron-shaped white stripes and a distinctive large 'horn' on the posterior end of its body.

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