Tomato hornworm caterpillars can be a problem in hydroponic systems, especially in greenhouses. These caterpillars can quickly defoliate tomato plants and eat flowers and fruit. Here are some ways to control tomato hornworms:
Hand-pick: Pick off caterpillars by hand and drop them into soapy water. Wear gloves if you don’t want to touch them.
- Use pesticides: Apply a low-risk pesticide like: Bacillus thuringiensis (Bt): A naturally occurring bacterium that’s effective on young caterpillars.
Spinosad: A soil-dwelling microorganism that affects the nervous system of caterpillars.
Insecticidal soap: Most effective on small caterpillars, but it doesn’t last long and needs to be repeated.
- Grow companion plants: Some plants can help deter hornworms.
Marigolds: Their strong scent can repel hornworms and other pests. For maximum protection, intersperse marigolds among your tomatoes. - Basil: :The scent of basil repels tomato hornworms and asparagus beetles. To make it more effective, you can gently touch the leaves to release their oils.
- Borage: Repels tomato hornworms and imported cabbageworm. Borage also attracts pollinators and beneficial insects, such as bumblebees.
- Nasturtiums: Repel tomato hornworms, Japanese beetles, and whiteflies. They also help with weed suppression and retaining soil moisture.
- Garlic: Deters many insect pests, including tomato hornworms, cabbage moths, flea beetles, carrot rust fly, aphids, and ants.
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Chives : Repel many common garden pests, including cabbage worms, aphids, carrot flies, and apple scab.
Tomato hornworms are the larvae of moths. The tomato hornworm moth is called the five-spotted hawkmoth. These moths lay eggs and die after a week or two.