How to Get Rid of Tomato Hornworms Naturally. Tomato hornworms destroy plants such as tomatoes, peppers, potatoes and eggplant, devouring the entire plant. Their large size should make them easy to find, but their green camouflage actually makes them hard to spot. However, with determination and persistence, you can manage them through natural means.
Spray the affected plants with a strong stream of water, and then immediately take a look. You'll see the hornworms as they thrash around.
Pick the hornworms off the plants and drop them in a bucket full of soapy water.
Release some beneficial insects such as laceworms, ladybugs and trichogamma wasps, which attack hornworm eggs. To be effective, do this before the hornworms manage to establish control.
Spray affected plants with natural insecticidal soap or with a tea made by infusing petunia leaves in water.
Plant some dill to serve as hornworm traps. Hornworms love dill, and once they infest the plants, they can be easily destroyed.
Sprinkle cornmeal around affected plants. Hornworms can't digest cornmeal, and the cornmeal will swell up and kill them.
Till your garden immediately after harvest to destroy pupae in the soil. This can kill up to 90 percent of the pupae, because at this stage, the hornworm pupae are large and can be found near the top of the soil.