How to Eradicate the Tomato Hornworm from the Garden

If you’re looking for tips on how to get rid of tomato hornworms in the garden, you’ve come to the right place. 

They might look plump and innocuous – but really, these pests are quite menacing. Tomato hornworms are large green caterpillars that can wreak havoc on many of the most common garden plants. 

It’s not just tomato plants that can be plagued by these bugs, either. They’re known to attack any plant in the nightshade family, including tobacco, peppers, eggplants, and potatoes.

Fortunately, there are several easy ways you can get rid of these pests for good. 

Ready to learn more about how to get rid of hornworms on tomatoes? Keep reading to find out more.

What Are Tomato Hornworms?

Tomato hornworms, or Manduca quinquemaculata, are large green caterpillars that are closely related to Manduca sexta, or tobacco hornworms.

Both pests cause extensive damage to the fruits, stems, and leaves of all plants in the Solanaceae, or nightshade family.

These pests can grow up to five inches long. While they can be quite shocking to behold when you finally notice them, they blend easily into the foliage of your plants so it may take some time before you are able to pinpoint the cause of destruction to your precious tomato plants. 

Tomato hornworms are the most destructive when they are caterpillars in the larval stage.

With a pale green color with black and white markings, the caterpillar’s most noticeable feature is its horn-like protrusions (hence the name!). They also have eight stripes, shaped like Vs

Do Tomato Hornworms Turn Into Anything?

Tomato hornworms are technically the larval form of adult moths known as hummingbirds or sphinx moths. The moths lay their eggs on the underbellies of leaves in the late spring. 

These tomato hornworm eggs hatch in a week, feeding for up to six weeks before creating a cocoon and overwriting in the soil. 

The moths emerge the following spring to continue the tomato hornworm life cycle, laying a fresh round of eggs on your unsuspecting plants. In warmer climates, there can be multiple generations of tomato hornworms each year.

Do Hornworms Only Attack Tomato Plants?

Despite the name, tomato hornworms can actually attack any garden plant – they just are notorious for feasting on fresh tomato crops.

Whether you have a spot in your garden for tomatoes or not, this is a pest you need to be wary of, and have a deep understanding of how to get rid of tomato hornworms in case of an outbreak.

What Damage Can Tomato Hornworms Do On Your Plants?

Learning how to get rid of tomato hornworms in the garden starts by knowing what to look for. You need to spot their damage quickly, otherwise, it’ll be too late by the time you find them.

Because they blend in so well with the scenery, regular inspections are necessary if you want to keep these pests at bay. 

They have the potential to totally decimate your plants. There are several clues that tomato hornworms are at work rather than some other kind of pest.

For starters, you’ll notice that the damage to your plants begins at the very top of the plant and works its way downward. 

Your plants might look chewed-on or be missing leaves. You might also notice dark black or green droppings on the top of the leaves. 

Look closely, and you’ll probably find the hornworms suspended beneath the leaves. You may also notice wilted leaves and plants that are severed at the stem entirely. 

One problem that often arises as a secondary issue of tomato hornworm infestation is sunscald. This occurs because there is reduced foliage cover on your plants.

How To Prevent A Tomato Hornworm Infestation In The First Place

Before we teach you how to get rid of tomato hornworms in your garden, we want to teach you how to prevent them in the first place!

There are several methods you can employ to prevent a hornworm infestation from decimating your crop. 

Fortunately, many of these prevention methods will help the health of your other plants, too.

General Garden Care Tips

You should till the soil at both the beginning and end of the gardening season to get rid of leftover larvae. 

Keep a clean garden space at all times, but especially at the end of the growing season. After you’ve harvested, it’s important that you take the time to clean up any leftover plants.

The following season, also rotate your crops. Don’t plant nightshade plants in the same location for two years in a row, as this can increase the likelihood of pest infestation (as a bonus, this can help prevent the spread and recurrence of disease).

Bring Beneficial Bugs To The Fight

You may want to consider keeping some beneficial insects around. Ladybugs, green lacewings, parasitic wasps, and other adult wasps are natural enemies of hornworms, and all feed on tomato hornworms and hornworm eggs.

Not all bugs are bad, and the aforementioned insects hunt out hornworms in the garden all on their own.

These bugs are easily purchased on the internet or at a garden store near you, and you can release them onto your plants.

They have no interest in your plants, but rather, the hornworms hiding on them!

Diatomaceous Earth

Another really great product to use as prevention, or even in your battle against a hornworm infestation, is Diatomaceous Earth.

You can spread this in your media, or apply it directly to your foliage with a sprayer, and it creates sharp edges that can kill tomato hornworms, along with a myriad of other pests.

Basically, any crawling insect will be cut open when they move across a shard, which will dry them from the inside out. It’s incredibly effective, and best of all, safe!

Learn more about how to use diatomaceous earth in our complete guide

Preventing Tomato Hornworm Infestations Indoors

If you’re growing indoors, the environment matters, too. While it’s unlikely that these pests will rear their ugly heads if you’re growing inside, they are common in greenhouse settings. 

Again, all the same preventative measures apply indoors as they do outside. Always water thoroughly and evenly, making sure you don’t overwater or underwater your plants.

How To Get Rid Of Tomato Hornworms In The Garden Naturally

Even with the best prevention measures, a stroke of bad luck is all it takes for an infestation to break out on your plants. So, let’s teach you how to get rid of tomato hornworms in the garden naturally, should an outbreak arise.

There are several methods of getting rid of tomato hornworms organically that you might want to consider. For one, you can simply handpick the pests from your plants. 

This is a good tactic if you have the time – although they look quite nefarious, they won’t bite or sting you. You can squish the bugs or drop them into a bucket of soapy water.

However, if you have a larger infestation and need to rectify it quickly, you need to use products to kill hornworms.

What Kills Hornworms On Tomato Plants?

There are several insecticides you can use to kill your tomato hornworms. These types of products may have gotten a bad reputation in the past, but these days, they’re really safe.

We carry a wide range of insecticides approved for organic use, so if you’re looking for methods of getting rid of tomato hornworms organically, you are in the right place. For the best results, look for a product with Bt.

Bt, or Bacillus thuringiensis, is a bacteria that is found naturally in the soil and poisons many larval insects. 

It must be applied to the plants’ foliage and has to be reapplied after it rains or you water your plants. Here are some of the best insecticides to kill hornworms on tomato plants:

• Safer Brand Caterpillar Killer Concentrate (OMRI Certified)
• Bonide Captain Jack’s Deadbug Brew Concentrate
• Monterey Lawn & Garden B.t. Concentrate

There are several insecticidal soaps you can use to get rid of tomato hornworms on your plants, too, but many of these are not necessarily safe to use in regards to pollinators – so consider whether this matters to you and your garden or not.

Does Neem Oil Kill Tomato Hornworms?

Neem oil can also be effective when you’re trying to get rid of hornworms in a more natural way.

Neem oil has an unpleasant, bitter taste that’s sure to keep pests away. It is safe for use even if you plan on harvesting tomatoes to eat later on.

We have an entire guide on how to use neem oil, so you can learn the right tactics for killing tomato hornworms with it!

When To NOT Kill Tomato Hornworms In The Garden

Although it sounds wrong, there are some situations in which you should leave the tomato hornworms in your garden alone. 

The most common? If you see tiny white ovals covering the length of the tomato hornworm’s body.

These look like tiny grains of rice but bugs with these markings are actually hosts to the larvae of the braconid wasp. These larvae feed on the tomato hornworms from the inside out, munching away until the wasp is ready to pupate. 

If you leave the parasites alone, they’ll eventually kill the hornworms when they emerge – and they’ll seek out other tomato hornworms to kill, too.

How To Attract This Beneficial Wasp To Kill Your Tomato Hornworms

If you want to attract braconid wasps to your garden, consider planting companion plants like dill, mustard, parsley, and yarrow. 

Adult braconid wasps feed on these plants’ nectar. You might also want to put out a source of water near your garden, like a birdbath or even an open saucer that you regularly refill. 

And again, make sure you don’t kill the hornworms with the larvae still attached! Be patient, and they’ll go to work for you.

Final Thoughts On How To Get Rid Of Tomato Hornworms

Tomato hornworms are frustrating pests to deal with and can even be a bother to master gardeners, but like all garden pests, they can easily be prevented and removed with a bit of patience and the right expertise. 

Now that you know how to get rid of tomato hornworms naturally, along with how to prevent them and identify them, you shouldn’t experience too much trouble even if these bugs do make their way onto your tomato leaves.

If you’re a tomato lover, consider reading our guides on how to grow hydroponic tomatoes and how to clone a tomato plant. These will provide you with some cool new tactics you can implement in your garden that may be new to you.

You can find all of your planting and pest control supplies at Hydrobuilder. Stock up today and you’ll benefit from the best prices and customer service – and a hornworm-free garden to boot!