Tomato hornworms are destructive tomato pests in the garden. Here's how to get rid of tomato hornworms before they kill your plants.

How to Get Rid of Tomato Hornworms: 12 Tricks That Work

Did you find the huge green tomato hornworms on your plants? Don’t panic! There are ways to get rid of tomato hornworms in your garden.

Tomato hornworms are destructive tomato pests in the garden. Here's how to get rid of tomato hornworms before they kill your plants.

Most gardeners will encounter tomato hornworms at some point. These dreaded pests cause serious damage; they literally destroy entire plants within a day or two. That’s why gardeners fear them so much, but you can get rid of tomato hornworms before they destroy your plants.

I don’t want you to fear a pest.

Tomato hornworms aren’t fun, but with the right planning and management, it’s possible to use naturals ways to get rid of tomato hornworms. If you have to end up using chemicals, it’s not the end of the world either!

It’s better than losing all of your hard work growing tomato plants.

First, gardeners need to understand the pest they’re dealing with before learning how to get rid of tomato hornworms. You also need to know how to prevent them in the first place.

Prevention matters the most!

Let’s dive in and keep reading to learn all about these tomato pests.

What Are Tomato Hornworms?

Tomato hornworms – Manduca quinquemaculata – is a garden pest that eats the leaves, fruits, and stems of different plants, especially ones in the nightshade family.

In your garden, you’ll find bright green caterpillars that measure up to five inches long with spikes or horns in their tails. Tomato hornworms are common throughout North America and Australia, targeting all nightshade plants like tomatoes, peppers, tobacco, potato, and eggplant crops.

How to Identify Tomato Hornworms

Tomato hornworms are destructive tomato pests in the garden. Here's how to get rid of tomato hornworms before they kill your plants.

A tomato hornworms look like a green caterpillar that measures around four inches long with seven white v-shape stripes running diagonally on their bodies. If you get close to them, you’ll notice large red or black horns that protrude out of their rear.

The most noticeable stage of these pests is in the juvenile larval stage when the huge caterpillars may be found in your plants, but they eventually turn into a moth with a five-inch wingspan.

The easiest way to identify that these are tomato hornworms is by their color. Tomato hornworms are the perfect green color to match tomato leaves. No other pest blends in with the plants as well as these.

Tomato Hornworms vs. Tobacco Hornworms

It’s easy to confuse tomato hornworms and tobacco hornworms; they both come from the same family of insects. They also both prey on nightshade plants, and gardeners treat them the same.

So, distinguishing the difference isn’t truly important.

However, the tobacco hornworm has a red-colored horn and diagonal white stripes instead of v-shaped stripes. Those are the only two differences, so you’ll need to look closely to identify the difference.

Understand the Tomato Hornworm Lifecycle

Tomato hornworms have four parts of their lifecycle. Generally, we only see the larvae stage, but a lot is happening before, and after that, we don’t see. Understanding how these pests grow and multiply is valuable for gardeners.

1. Eggs

The adult female sphinx moth lays eggs on plants in the nightshade family, such as tomatoes, peppers, eggplants, and potatoes.

Eggs hatch within three to five days after being laid on the plants, and the worms start to grow rapidly. That leads to the next stage.

2. Larval Stage

Most gardeners see the larval stage. That’s when you find a huge, fat, green worm on your tomato plants.

Believe it or not, those huge worms aren’t the adult stage, despite their massive size. This stage is broken down into five stages called instar stages. The larval stage lasts around three weeks, and an average tomato hornworm reaches up to five inches long and weighs 10 grams.

That’s a huge pest!

3. Pupae Stage

A tomato hornworm is essentially a large caterpillar. When cold weather arrives, they overwinter in the soil as large, reddish-brown pupae.

4. Adult Hornworms

The last stage of the cycle is the adult stage. In the late spring, the pupae hatch, and a large moth comes out, known as the five-spotted hawk moth or the sphinx moth.

This is the adult stage, and they feed on the nectar of different flowers in the evening into the early morning. They are hard to spot because they aren’t out in the daytime when we are in the garden.

The adults also lay eggs, continuing the tomato hornworm lifecycle.

Damage Caused by Tomato Hornworms

Most gardeners will see signs of the tomato hornworm before finding the larval stage on their plants. It’s hard to spot the worms because they camouflage so well with the color of the plant. Also, the signs of these pests are similar to other pests.

If you’re wondering if your plant damage is caused by tomato hornworms or not, here are a few signs.

1. Black Droppings

Check your plants to see if you find any black droppings left on the leaves of the plants. The hornworms leave the droppings behind as they munch through the plants.

2. Check in The Evenings

Tomato hornworms are most active at dusk, dawn, and at night. This is when they come out to feed, and while their camouflage makes spotting them a bit harder, they thrash and move, so bring a flashlight when eating and check out your plants.

The best light to use to find tomato hornworms is a UV flashlight. These pests glow under a UV flashlight, making your plant look like it has bulbs on it.

3. Large Holes in the Plant Leaves

Tomato hornworms aren’t shy about their damage. They eat the leaves superficially, leaving huge holes and open spots where they’ve eaten all the plant matter.

Over time, the defoliation increases. You should check daily for these caterpillars because, if you don’t, you can lose entire plants.

How to Get Rid of Tomato Hornworms Naturally

You don’t have to resort to chemicals to get rid of tomato hornworms. Natural methods work, especially if the infestation isn’t severe yet.

1. Till The Soil

Tilling the soil is a controversial topic nowadays, and more people are turning to no-dig gardening methods. However, the pupae bury themselves into the soil to overwinter before the adult hatches in the spring.

Tilling the soil exposes the pupae to the cold weather, killing them. If the adults aren’t in your garden, then you won’t end up with the larvae worms either.

2. Hand Pick Tomato Hornworms Off Your Plants

Perhaps the most common way to get rid of tomato hornworms naturally is to handpick them off your plants.

Let’s be honest; no one wants to touch these things. I suggest using gloves, but chickens really love to eat hornworms as a yummy snack that’s full of protein.

Don’t let these pests go to waste after all!

When you handpick tomato hornworms, carefully inspect your plants once or twice per day. Look at the stems and the tops and bottoms of the leaves. They camouflage well, so you need to inspect carefully.

If you don’t have chickens to feed them, you can drop them into a bucket of soapy water or crush them with your foot.

3. Use Companion Planting

Companion planting is a great, natural way to get rid of tomato hornworms. Basil planted near your tomatoes improves the flavor of the fruits while simultaneously repelling the hornworms away from these plants.

Another companion plant that works well against hornworms is borage. Borage also attracts pollinators and beneficial insects to your garden.

Planting flowers near your vegetable garden has many benefits! Other companion plants that help to get rid of tomato hornworms include:

  • Parsley
  • Yarrow
  • Dill
  • Mustard
  • Marigolds

4. Plant Trap Crops

Trap crops are a crop that you plant near the infested plants but far away that you’re pulling pests away from the garden.

When it comes to hornworms, plant flower tobacco plants. The sphynx moth loves this plant.

5. Rotate Crops

Another natural way to reduce or get rid of hornworms in the garden is to always use crop rotation. This isn’t a true preventative measure, but it helps to reduce the pupae in the soil that will turn into egg-laying moths.

6. Release Natural Predators and Beneficial Insects

Beneficial insects prevent and control populations of hornworms. The two most effective ones to release are ladybugs and lacewings. Online nurseries and garden stores sell these predators because they eat eggs and other pests in your garden.

Another effective natural predator of tomato hornworms is the paper wasp. It feeds on different caterpillars, so if you aren’t sure it’s the tomato hornworm, releasing paper wasps is a great idea since they target all caterpillars.

7. Spray Plants with a Homemade Cayenne Pepper Spray

Instead of resorting to chemicals, consider making a homemade garden spray with cayenne pepper, water, and soap. Then, spray it directly onto your tomato plants.

The capsaicin in the cayenne peppers forces the hornworms away, and you can find them more easily on the ground. It might also kill them.

You’ll need to spray your plants regularly for this homemade garden spray to work.

How to Get Rid of Tomato Hornworms with Chemicals

Sometimes, we have to turn to chemicals. Not all chemicals are “bad,” but if you’re like me, spraying or using anything on your garden requires consideration. It should be a last ditched effort.

8. Try B.T.

Bacillus thuringiensis, typically called BT, is an effective, natural chemical that you can use to treat your plants and get rid of tomato hornworms. BT is short-lived in the garden and works well on the young caterpillars.

BT is a natural bacterium found in soil, and when the hornworms (or any pest) consume it, it causes their digestive system to paralyze. Eventually, the pests stop feeding entirely, causing them to die.

Many gardeners prefer to use BT because it doesn’t harm humans, pets, or kids.

My favorite B.T. to use is Monterey B.T. Concentrate. This container lasts forever, and it’s certified by the OMRI.

9. Monterey Garden Insect Spray

My next favorite insecticide that I use to get rid of tomato hornworms is the Monterey Garden Insect Spray. It controls caterpillars, leafminers, borers, fruit flies, and more.

It works fast, and it’s odorless. They used fermentation to treat the plants quickly, and you can use it on law

10. Use “Safer Brand” Garden Dust

Another insecticide that works well for hornworms is garden dust, and I like the Safer Brand because it is also certified by the OMRI. You don’t need to worry that beneficial insects will be harmed; it’s totally safe!

11. Safer Brand Caterpillar Killer Concentrate

Safer Brand also makes Caterpillar Killer that works for trees, shrubs, and vegetable plants. It kills caterpillars, but it won’t hurt earthworms, birds, or beneficial insects. No ladybugs or honeybees are harmed with this product!

12. Spray with Neem Oil

Neem oil has its pros and cons. The biggest negative is that it often kills beneficial insects as well as the pests you want to get rid of, so many gardeners use it as a last resort.

However, if you’re really struggling with the tomato hornworm population in your garden, give neem oil a try.

How to Prevent Tomato Hornworms

Use Row Covers

One of the best ways to prevent tomato hornworms in the garden is to not allow the moths to reach your plants at all. When you plant your nightshade plants, cover them with floating row covers or a high tunnel until they need to be removed for pollination.

If the moths can’t get to your plants, they’re unable to lay eggs. That stops the problem in its tracks.

Try making one of my $20 mini hoop houses!

Try Diatomaceous Earth

Some say that diatomaceous earth helps to get rid of hornworms, while others say it works better at preventing them.

The good thing about DE is that it is harmless to humans and pets unless inhaled, so make sure you wear a mask when using it. However, it harms caterpillars because it feels like shards of glass when they crawl over it, shredding their bodies.

If hornworms crawl over the diatomaceous earth, they’ll get dehydrated and die over time. It works best on young hornworms.

Use Black Plastic

Another way to prevent hornworms in the garden is to cover your garden with black plastic to stop the moths from emerging in the spring. When you do this, you break the lifecycle, and they’ll die before they can lay new eggs on the plants.

If you don’t want to use black plastic, another option is using a thick layer of cardboard around your plants.

Finding tomato hornworms in your garden is always a moment of panic, but remember, you can get rid of tomato hornworms with a little work. Your plants won’t die unless you refuse to treat them.

Have you ever dealt with tomato hornworms? Let me know how you took care of them in your garden.

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