Caterpillar with red horn


The caterpillar with red horn is also known as the tomato hornworm, and if you are growing Tomatoes its almost a sure thing that you have to meet them.


 Defending Your Tomatoes: A Gardener’s Guide to Outsmarting Hornworms

Ah, the joy of witnessing your tomato plants flourish is truly unmatched. But alas, in comes a garden nemesis, the hornworms, to dampen this joy. Two primary culprits, the tomato hornworms and tobacco hornworms, are infamous for their love of tomato plants, but they don’t stop there. They also have an appetite for other members of the Solanaceae (nightshade) family such as eggplants, peppers, tobacco, and potatoes. Despite their considerable size, their green hue allows them to blend seamlessly with foliage, making them a stealthy foe.

Identifying the Attack

The damage inflicted by these voracious eaters is hard to ignore. They feast non-stop, leaving behind a trail of spotty, chewed leaves and fruit. Their meal of choice includes entire leaves, small stems, and occasionally, they nibble on the fruit too. Although their large size should make them easily noticeable, their camouflaging color does an excellent job at hiding them in plain sight. It’s often the sight of devastated foliage that signals gardeners to their presence.

Deploying the Defenses

  • Handpicking: Due to their size, a simple yet effective control method is handpicking them off the plants. Once captured, a bucket of soapy water will be their end.
  • Beneficial Insects: Introducing predators such as lacewings, braconoid and trichogramma wasps, and ladybugs can significantly reduce their population. These beneficial insects prey on hornworm eggs, providing a natural line of defense.
  • Natural Pesticides: For severe infestations, employing least-toxic, short-lived natural pesticides like Safer Garden Dust or Monterey Garden Insect Spray can offer a respite, especially against younger caterpillars. Following up with the release of predatory insects will help maintain a hornworm-free garden.
  • Diatomaceous Earth: A sprinkle of 100% organic Diatomaceous Earth (DE) can provide long-lasting protection. DE, a powder of fossilized aquatic organisms, acts like broken glass to insects, scoring their outer layer as they crawl over it.
  • Targeted Organic Insecticides: If the situation calls for it, spot treat with a fast-acting organic insecticide, ensuring to reach the undersides of leaves and deep into the plant canopy where these pests lurk.
  • Post-Harvest Roto-tilling: After you’ve harvested your produce, roto-tilling the soil can destroy overwintering pupae, preventing a resurgence in the next growing season.

Preventive Measures

Planning for a hornworm-free garden next season? Intercropping with dill, basil, or marigolds can deter them. Interestingly, some hornworms may be found with parasitic wasp larvae attached, resembling grains of rice. These wasps are allies, as they eventually kill the hornworms. If you spot such a hornworm, consider relocating it far from your garden to allow the wasps to complete their lifecycle without any collateral damage to your plants.

Tilling the soil at the start and end of each gardening season also helps in destroying overwintering larvae, with studies showing up to 90% mortality.


  • How do I differentiate between tomato hornworms and tobacco hornworms?
  • Are there other organic methods to control hornworms?
  • How can I attract more beneficial insects to my garden?
  • What are other common pests of tomato plants and how can I control them?

Concluding the Battle

Being proactive and employing a combination of these defensive strategies will ensure your garden remains a bountiful haven rather than a banquet for hornworms. Here’s to victorious gardening and abundant harvests!

Back To Top