Tomato and Tobacco Hornworms
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 hornworms 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.
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.
SCOUTING
- 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.
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 with types that are not attacked by hornworms.
- Larvae can be handpicked; they are easiest to see at dawn and dusk.
- 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.
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