Andre CampbellTomato hornworms are among the most destructive pests found in vegetable gardens.
They primarily target tomatoes, peppers, eggplants, and other nightshade crops. These large green caterpillars can strip plants of leaves and even damage fruit in just a few days.
Fortunately, several natural and organic methods can help you control hornworms without resorting to harsh chemical pesticides.
Identification
Tomato hornworms are the larval stage of the five-spotted hawkmoth [1]. They are large, green caterpillars with horn-like tails.
Mature tomato hornworms can grow as long as 4 inches (10 cm). They are among the largest caterpillars often found in vegetable gardens, where they can be a problem for plants.
Tomato hornworms can cause damage to your tomato plants and other crops, like pepper plants. They can strip a plant of its leaves very quickly [2].
They also feed on other members of the nightshade family. This includes tomatoes, peppers, eggplants, potatoes, and occasionally tobacco.
Because they blend in so well with tomato foliage, gardeners often overlook them until significant damage has occurred.
Lifecycle
Tomato hornworms begin life as eggs laid by adult five-spotted hawkmoths. After hatching, the caterpillars feed on tomato and other nightshade plants for several weeks.
Mature hornworms then burrow into the soil, where they pupate. Adult moths later emerge, mate, and begin the cycle again.
Signs of a Tomato Hornworm Infestation
Look for these common signs:
- Missing leaves or large holes in foliage.
- Bare stems where leaves have been stripped away.
- Chewed green tomatoes.
- Large green caterpillars hiding among the foliage.
- Dark green or black droppings (frass) on leaves and beneath plants.
When to Take Action
Tomato hornworms can consume large amounts of foliage in a short period.
If you spot one or more caterpillars on a plant, it’s best to remove them right away. This action can help prevent significant damage to the plant.
How to Find Tomato Hornworms
Because tomato hornworms blend in with foliage, they can be difficult to spot.
To find them:
- Look for damaged leaves and follow the damage upward.
- Search for droppings on leaves and the soil below.
- Check stems and the undersides of leaves.
- Use a blacklight at night, as hornworms glow under ultraviolet light.
Gardener’s Tip: If you suspect hornworms but can’t find them, inspect your plants at dusk or after dark with a flashlight or UV light. Hornworms are often easier to spot when they are actively feeding.
How to Get Rid of Tomato Hornworms Naturally
If you’ve got a tomato hornworm problem, don’t worry! As mentioned, you can take a few steps to keep them off your plants naturally.
Below, we will talk about these remedies in detail.
1. Pick Them Off
It may seem like a lot of work, but squishing those green caterpillars on your tomato plants is satisfying.
If you don’t want to squish them, place them away from your garden where birds and other predators can find them. You can also drop them into a bucket of soapy water.
2. Row Covers
Another way to prevent tomato and tobacco hornworms from attacking your crops is to cover the plants with floating row covers.
These will keep moths from accessing your plants and laying eggs. For best results, install row covers before moths arrive and remove them when pollination is needed.
3. Soap and Water
A combination of soap and water is another excellent home remedy for controlling tomato hornworms. That’s right, soapy water.
Spraying plants with mild soapy water can make hornworms easier to spot and remove. Simply mix a small amount of soap and water in a spray bottle and lightly mist the plants.
If you collect the caterpillars and drop them into a bucket of soapy water, they will die.
4. Repellent Plants
This tactic is another way to control tomato hornworms organically. It involves growing specific crops side by side to benefit from their mutual support.
Some gardeners report fewer hornworm problems when growing basil, dill, borage, chamomile, and nasturtiums near tomatoes. These plants may also attract beneficial insects that prey on hornworms and other garden pests.
5. Trap Crops
You can plant trap crops around the perimeter of your garden or wherever you see signs of these caterpillars. These plants help keep certain critters away from your main crops.
The best trap crop for tomato hornworms is flowering tobacco plants. The hornworms are attracted to flowering tobacco plants and may leave your tomatoes and other crops alone.
6. Crop Rotation
Crop rotation is the practice of planting different crops in the same garden area each growing season [3].
So, you will plant another crop in the tomato spot next growing season. This method will help break the pest life cycle and improve your soil’s fertility.
Growing tomatoes in a different spot each season may help reduce some overwintering pests and diseases.
7. Natural Predators
Tomato hornworms are no match for their natural predators.
Braconid wasps are among the most important natural enemies of tomato hornworms. Birds, ladybugs, and green lacewings may also help by feeding on eggs and young caterpillars.
Therefore, try to attract and retain these creatures. Let them do their jobs.
They will help control the caterpillars on your tomato plants.
8. Cayenne Pepper Spray
Some gardeners use cayenne pepper spray to discourage hornworms and other pests from feeding on plants.
So, create a homemade cayenne pepper spray by mixing cayenne pepper, water, and soap. The soap will help the spray adhere to the plants.
Mix one tablespoon of cayenne pepper with one cup of water and one teaspoon of dish soap. Apply it to all plant surfaces.
9. Bacillus thuringiensis
Bacillus thuringiensis, or Bt for short, is toxic to some caterpillars. They include tobacco, cabbage, pepper, and tomato hornworms.
Bt has a long history of safe use in organic gardening. Mix this organic insecticide according to the instructions, then spray it on your plants.
10. Neem Oil
Neem oil is a natural, organic pest-control remedy that is very easy to use.
Mix 1 tablespoon of neem oil with 1 teaspoon of liquid soap and 1 gallon of water, then spray it on your plants.
Neem oil may help deter feeding by young hornworm larvae and can interfere with their development. This home remedy may also reduce egg-laying by adult moths.
11. Till the Soil
Suppose you had a lot of tomato hornworms last season. If so, just till the soil around your plants next year. Doing so will help expose and destroy overwintering pupae.
12. Diatomaceous Earth (DE)
It works by damaging the protective outer layer of insects, causing them to lose moisture and eventually die. However, DE is generally less effective against large, mature tomato hornworms than handpicking or Bt.
Sprinkle some DE on your plants.
You can also make a DIY spray by combining one part DE with four parts water. Shake well and coat your plants. The spray starts working once it dries.
13. Hose Them
These pesky insects are no match for a gardener armed with a hose. Turn on the hose and direct the water onto the hornworms.
The force of the water will knock them off the plants. You can then collect them and dispose of them.
14. Beneficial Nematodes
Beneficial nematodes can attack hornworm pupae and other soil-dwelling stages of certain pests. By doing this, they help lower future pest populations.
Mix them with water and apply them to your garden according to the instructions included with your purchase.
15. Check for Parasitized Hornworms
If you find a hornworm covered with small white cocoons, leave it alone. These cocoons belong to braconid wasps, beneficial insects that naturally kill hornworms.
The hornworm will soon die, and the emerging wasps will help control future infestations.
Best Organic Products for Tomato Hornworms
16. Azera Gardening
There’s no need to reach for toxic insecticides. Azera Gardening’s organic insecticide is as effective and much safer for you and the environment.
It combines naturally derived pyrethrins and azadirachtin to control caterpillars and other garden pests. This pesticide can quickly control caterpillars and other garden pests through contact and feeding activity.
17. Bug Buster-O
Bug Buster-O is a potent, natural formula. It’s great for people who want to get rid of caterpillars eating tomatoes and other plants.
Moreover, it is eco-friendly and safe for the environment. It also works against many other garden pests.
18. ECOWORKS EC
This product is specially formulated to control many insect pests, including hornworms. It’s also safe for use around children and pets, and it works against fungal diseases.
How to Prevent Tomato Hornworms
- Inspect plants regularly.
- Encourage beneficial insects.
- Rotate crops.
- Remove plant debris after harvest.
- Till the soil in spring or fall.
- Use row covers early in the season.
Frequently Asked Questions
Are tomato hornworms poisonous?
No. Tomato hornworms are not poisonous to humans.
Do tomato hornworms bite?
No. The horn-like tail is harmless and cannot sting.
What do tomato hornworms turn into?
Tomato hornworms become five-spotted hawkmoths.
Will hornworms kill a tomato plant?
A large infestation can severely weaken or defoliate a plant. However, healthy tomatoes often recover if the pests are removed quickly.
Are tomato hornworms beneficial?
No. The caterpillars damage crops, though the adult moths may help pollinate flowers.
Takeaway
If you’ve ever grown tomatoes, sweet peppers, eggplant, and potatoes, you may know that tomato hornworms can ruin your crop quickly. Luckily, these safe and natural remedies can help keep these pests under control.
Sasha Campbell
I really wish that you would allow us to print the information. It is exactly what I am looking for, but I need to reference it, decide which method will work best for me–then mix the components. I am always in my gardening clothes with dirt and gloves and I am not in the mood or the attire to come inside and pull it up on the computer, write it down and then go back to mix it. I am not–I repeat, NOT–trying to steal anything, but the help I feel has been offered, is limited at best.