Have you noticed big green caterpillars eating your tomato plants? Then your crops are likely being feasted on by tomato hornworms – or their closely related cousins, tobacco hornworms. Common tomato pests, these greedy caterpillars can quickly strip the foliage of tomato plants as well as peppers, eggplants, and potatoes. You will need to act fast to get rid of hornworms, as they can get through a vegetable plot in record time.
Tomato hornworms are larvae of the five-spotted hawkmoth (Manduca quinquemaculata), and are more prevalent in northern states, while tobacco hornworms are larvae of the Carolina sphinx moth (Manduca sexta) and are more common in the South. Managing these pests is key to growing perfect tomatoes by nurturing healthy, productive plants.

In the future, try to manage infestations by repelling the moths and their larvae from your plants, using the methods outlined below.
1. Pick Them Off By Hand
It might sound unpleasant, but hand-picking tomato hornworms is the best way to control an active infestation. Hornworms do not bite and their large size makes them easy to handle. Wear gloves if you are squeamish! Check over plants daily – the best time to do this is in the evening, when the caterpillars are most active. Shine a flashlight over the plants, to highlight the caterpillars, and carefully examine each leaf and stem, looking underneath leaves as well as on top. When you spot a hornworm, pick it off the plant and drop it straight into a bucket of soapy water. Alternatively, if you have chickens, then save the hornworms to use as feed. They will love to feast on them.
2. Repel Them With A Homemade Spray
If you can’t manage – or bear – to handpick hornworms, then you could treat them with a homemade spray. This recipe uses cayenne pepper, which is detested by hornworms. It’s a deterrent rather than a cure, but can also kill them: In a bottle, add 1 cup of water, a teaspoon of dish soap, and ¼ teaspoon of cayenne pepper. Shake to mix. Spray over plants’ leaves, including the undersides. You will need to do this several times per week, especially after it rains. Instead of adding to the spray, you can lightly sprinkle cayenne pepper directly over affected areas.
3. Use Bacterial Insecticide
If you are struggling to manage tomato hornworms, then try using Bacillus thuringiensis (Bt), a natural pesticide allowed in organic farming. Bt is a naturally occurring bacterium, common in some soils, that causes disease in certain insects – notably leaf and needle-feeding caterpillars. It contains a crystal protein, which paralyzes the hornworms’ digestive system. Over a period of a few days, they will stop feeding and starve to death. Bacillus thuringiensis is harmless to humans and beneficial insects, although it will kill butterfly larvae, so only use it on affected crops where there is an active infestation. Usually applied as a spray, It is most effective when the caterpillars are young and have not had a chance to cause severe damage. So check plants daily.
4. Attract Predatory Insects
Predatory insects are your best friends in the fight to control tomato hornworms, doing the dirty work for you. However, they are not an instant solution and should be encouraged as part of a long-term control plan. Braconid wasps lay their eggs on tomato hornworms, and the larvae eat the caterpillar from the inside out. If you find a tomato hornworm caterpillar in your garden covered with white rice-like sacks, leave it alone as the wasps will mature and the hornworm will die. The mature wasps will then create more wasps and kill more hornworms. Ladybugs and green lacewings will also feed on young caterpillars or eggs. Both can be purchased and added to gardens. You can attract predatory insects to your yard by including favorite plants such as alyssum, dill, yarrow, white clover, and marigolds.
5. Deter Hornworms With Companion Plants
Tomato companion plants are invaluable in the control of tomato hornworms and other pests such as thrips and aphids. Their flowers or foliage produce a strong scent that repels bad bugs, yet are often a draw for beneficial and pollinating insects. Borage, basil, marigolds, and nasturtiums are particularly effective – interplant them among your tomato crops. As well as controlling pests, companion planting has other benefits, helping to boost nutrients and even improve flavor.