Tomato and tobacco hornworms are large caterpillars that feed on tomatoes and other nightshade-family plants. A few caterpillars can remove substantial foliage, but home-garden infestations can often be managed by inspection and hand removal.
Identify the Caterpillar and Damage
- Tomato hornworm (Manduca quinquemaculata): Larger larvae typically have eight white V-shaped marks on each side and a dark horn.
- Tobacco hornworm (Manduca sexta): Larger larvae typically have seven diagonal white stripes and a reddish horn.
Both may occur on tomato, pepper, eggplant, potato, and related weeds. Look for missing leaves near the top of a plant, chewed fruit, bare petioles, and dark green or black droppings. Start at the fresh damage and inspect stems and leaf undersides; the green caterpillars are easy to overlook.
Check for Beneficial Insects First
A hornworm covered with small white, rice-like cocoons has been parasitized by a braconid wasp. Leave it in place or move it away from valued foliage so the adult wasps can emerge and search for more hornworms. Lady beetles, lacewings, paper wasps, and other predators may attack eggs or young larvae.
Control Options in Priority Order
- Handpick. Wear gloves if preferred, remove caterpillars, and relocate or dispatch them according to your garden practice. Inspect at least twice a week while damage is active.
- Reduce alternate hosts. Manage nightshade-family weeds near the crop. After harvest, remove badly infested crop residue; soil cultivation may expose some pupae where tillage is appropriate.
- Protect young plants. Insect-exclusion fabric can prevent egg laying before flowering, but edges must be sealed and covers managed so they do not overheat plants or interfere with pollination and access.
- Treat small larvae if necessary. A product containing Bacillus thuringiensis var. kurstaki (Btk) must be eaten and works best on young caterpillars. Spinosad and insecticidal soap are additional options on products labeled for the crop and pest.
Does Neem Oil Kill Hornworms?
Neem products are not a reliable instant knockdown for large hornworms. Some labeled formulations may reduce feeding or development when young larvae contact or ingest treated foliage, but concentration, formulation, coverage, and label directions matter. For a few large caterpillars, hand removal is usually more direct.
Pesticide and Pollinator Safety
Use a pesticide only when the product label lists the crop and intended use. Follow the rate, protective equipment, re-entry interval, preharvest interval, application timing, and disposal directions. Spinosad can harm bees while spray is wet, and broad-spectrum insecticides can remove the beneficial insects that help suppress hornworms. Do not apply homemade mixtures whose plant safety and legal use are unknown.
For detailed identification and management, see University of Minnesota Extension's hornworm guide. Browse Grow Organic's tomato hornworm treatment collection or review the pest-control solution chart.