How To Get Rid Of Hornworms

If you’ve found large, green caterpillars stripping your tomato plants bare, you’re likely dealing with hornworms. Learning how to get rid of hornworms is essential for any gardener wanting to protect their nightshade family crops. These hungry pests can decimate a plant overnight, but with a few simple strategies, you can take back control of your garden.

These methods range from hands-on removal to encouraging natural predators. The best approach is often a combination of several techniques.

1. Handpicking: The Most Immediate Solution

This is the quickest and most effective method for a light infestation. It requires no special tools, just a keen eye and a steady hand.

Best Time to Hunt: Go out at dawn or dusk with a flashlight. The light makes their bodies glow slightly, making them easier to spot against the green leaves.
What to Do: Wear gloves if you prefer. Simply pick the hornworms off the plant. They are not harmful to humans, despite their intimidating horn.
Disposal: Drop them into a bucket of soapy water. This is the most effective way to ensure they don’t return. You can also feed them to your chickens if you have them.

2. Invite Natural Predators to Your Garden

Creating a balanced ecosystem is the best long-term defense. Many common birds and insects see hornworms as a tasty meal.

Birds: Encourage birds like chickadees and robins by putting up birdhouses and a birdbath. They are excellent at finding and eating caterpillars.
Parasitic Wasps: If you see a hornworm covered in white, rice-like cocoons, leave it! Those are the pupae of braconid wasps. The wasp larvae have already killed the hornworm, and the new generation will hunt more.
Ladybugs & Lacewings: While they prefer aphids, they contribute to a healthy insect balance that supports overall pest control.

3. Use an Organic Bt Spray

Bacillus thuringiensis, or Bt, is a natural soil bacteria that is harmless to people, pets, and beneficial insects but lethal to caterpillars.

Purchase a Bt spray labeled for caterpillar control (often Bt kurstaki).
Mix and apply it directly to plant leaves, especially the undersides, in the late afternoon.
The caterpillar eats the treated leaf and stops feeding within hours, dying shortly after. Reapply after rain or every 7-10 days as needed.

4. Till Your Garden Soil Seasonally

Hornworms overwinter as pupae in the soil. Disrupting their life cycle is a powerful preventative measure.

After the harvest season, till your garden soil thoroughly. This brings the pupae to the surface where they will freeze or be eaten by birds.
Do this again in early spring before planting. This can significantly reduce the number of adult moths that emerge to lay eggs.

5. Try Companion Planting

Certain plants can help deter the adult sphinx moth from laying eggs in the first place.

Strong-Scented Herbs: Plant basil, marigolds, dill, or borage around your tomatoes and peppers. Their strong scents can mask the smell of the host plants.
Trap Crops: Some gardeners find that planting dill or nicotiana away from your main crops can attract the moths to lay eggs there instead, making the pests easier to manage.

6. Apply Diatomaceous Earth for Young Larvae

Food-grade diatomaceous earth (DE) is a fine powder made from fossilized algae. It works on small, young caterpillars by dehydrating them.

Dust a light coating on dry leaves, focusing on the undersides.
Reapply after watering or rain, as it loses effectiveness when wet.
Note: DE can also affect beneficial insects, so use it sparingly and targeted, not as a broad broadcast.

What to Look For: Signs of Hornworm Damage

Often, you’ll notice the damage before you see the well-camouflaged caterpillar. Look for these key signs:

Large sections of leaves missing, starting from the top of the plant.
Black or dark green droppings (frass) on leaves below the damaged area.
Stripped stems, which can sometimes be mistaken for deer damage on smaller plants.

Prevention is Key: Stopping Them Before They Start

A few habits can make your garden less inviting. Rotate your crops each year so pests can’t build up in the soil near their favorite food. Keep your garden clean of plant debris in the fall. And always inspect new transplants carefully before putting them in your garden, as they can sometimes hitch a ride.

FAQ: Your Hornworm Questions Answered

What kills hornworms instantly? Handpicking and dropping them into soapy water is the fastest manual method. For a spray, Bt is very effective once ingested by the caterpillar.

What is a natural predator for hornworms? Braconid wasps are their primary natural predator. Birds, ladybugs, and green lacewings also help control populations.

Should I remove hornworms with white eggs? No! Those white capsules are the cocoons of parasitic braconid wasps. Leave that hornworm in place so the wasps can hatch and continue their beneficial work in your garden.

What plants do hornworms hate? They are deterred by strong-smelling herbs like basil, mint, and sage when planted as companions near tomatoes and peppers.

Does vinegar kill hornworms? A direct spray of vinegar may kill a caterpillar, but it is more likely to severely damage your plants leaves. It is not a recommended or reliable control method compared to others listed here.

By combining regular monitoring with these simple, effective tactics, you can protect your tomatoes, peppers, and eggplants from these hungry pests. The goal isn’t always total elimination, but managment, allowing you to enjoy a healthy and productive garden all season long.