Tomato and Tobacco Hornworms

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Tobacco Hornworm Life Stages Tomato Hornworm Life Stages

Tomato Hornworm Caterpillar and Tomato Fruit Feeding DamageTomato Hornworm Caterpillar and Tomato Fruit Feeding Damage

Hornworm FeedingHornworm Feeding

Severe Feeding Damage on TobaccoSevere Feeding Damage on Tobacco

HOSTS

  • Tomato
  • Pepper
  • Potato

DESCRIPTION

Adults are large moths also known as sphinx, hawk, or hummingbird moths. Larvae are large, cylindrical and usually green in color. Tomato hornworm larvae have eight white “v” shaped marks along each side and a black horn at the end of its body. The tobacco hornworm has seven diagonal white stripes along its body and a horn at the end of its body that is usually orange or red.

BIOLOGY

Egg | Larva | Pupa | Adult
Hornworms are present around July through the end of the season. They have 1-2 generations per year and overwinter as pupae in the soils.

  • Larval populations peak in midsummer
  • Start monitoring in early July
  • Larvae are easiest to see when actively feeding near dusk and dawn
  • Visually monitor plants for feeding damage, defoliation, larvae, dark droppings, or fruits with large, deep, cavities

SYMPTOMS

Larvae use chewing mouthparts to feed primarily on leaves, but will also eat blossoms, stems, and fruits, leaving behind dark green or black frass. Larvae can defoliate plants and scar fruit, especially when populations are high.

GENERAL MANAGEMENT

Hornworm populations often do not cause economic injury due to predation from natural enemies. However, localized plant defoliation in backyard gardens or in high tunnels can occur.

  • Plow field after harvest to destroy pupae
  • Rotate crops
  • Larvae can be handpicked.
  • Spot treat infected plants; Bt and spinosad are effective

INSECTICIDES

Consider treatment if larvae are causing extensive defoliation, or if they are feeding on fruit.

Click here to view insecticide options.











Precautionary Statement: Utah State University and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document. All pesticides are labeled with ingredients, instructions, and risks, and not all are registered for edible crops. “Restricted use” pesticides may only be applied by a licensed applicator. The pesticide applicator is legally responsible for proper use. USU makes no endorsement of the products listed in this publication.