How to Identify and Get Rid of Hornworms

How to Get Rid of Hornworms in Your Garden

When it comes time to get your garden going, we’re always here to help. Our staff of experienced and dedicated writers strive to provide you with a library of well-researched, well-written articles that provide you with the knowledge, tricks and tips you need to ensure your time spent in the garden means less work and more fun. Most importantly though, we want you to enjoy the fruits of your labor and that means a healthy bounty come harvest time.

Tomato Worms or Tomato Hornworms…Ugly Any Way You Say It

The focus of this article will be how to get rid of hornworms in your garden. Tomato worms, also called tomato hornworms can put a real damper on your hopes of a healthy harvest by their relentless attack on your beautiful tomato plants.

World-wide, the most beloved fruit in the garden is by far, the tomato. We have numerous articles available on planting and harvesting as well as the best types of tomatoes to grow and even a list of some delicious tomatoes you may have never known existed. In this article, however, we going to show you ways to keep from sharing your garden with uninvited guests.

We’ve gathered up some good information on what to look for when it comes to protecting your tomatoes against tomato hornworms. Read on to learn how to deal with these pests naturally and effectively. Remember, they are there to destroy your garden but we are here to prevent that from happening. So let’s get started. 

Tomato Hornworms

If you’ve ever grown tomatoes, you are likely familiar with that green grinch of the garden, the Tomato Hornworm. The hornworm (Manduca quinquemaculata) is actually the larval stage of the five-spotted hawk moth, also called the sphinx moth, of the family Sphingidae. They are also known as Hummingbird Moths.

Hummingbird Moth Image Credit: © Alan Ray

 

Tomato worms are huge, green caterpillars that chew incessantly and eat the leaves of tomato plants. They can strip an entire plant clean of foliage in no time. They also chew holes in fruit when given the chance. In this stage of their life they are mercilessly destructive.

As caterpillars, the tomato hornworm’s name comes from the distinct hook-like horn protruding from their posterior. Miraculously, after pupating, these tomato worms are transformed into moths. These moths are known as Hummingbird moths. Fascinating little creatures resembling a hummingbird when mature, they happily go about pollenating flowers. It’s hard to imagine these cute little creatures as the same devastating little monsters they are when caterpillars.

Their eggs, laid on the underside of the leaf of their host plant, hatch quickly, usually within four to five days. Once hatched, they are voracious eaters and can seriously damage a plant in a very short amount of time. This is why daily inspection of your plants is crucial because if you wait until the weekend…they are a few days of devastation ahead of you.

A Tip About Aphids

While you’re looking for signs of the hornworm or its eggs, be sure to check the underside of the leaf for aphid eggs as well. This is where aphid offspring are born and/or laid and hatched. There are about 250 species which are actually harmful to agriculture. Some aphids are born live and begin feeding on the host plant immediately upon birth. Others dine and spread a virus onto the plant that kills it eventually. Aphids are nasty little bugs you don’t want hanging around your little garden of Eden so as you inspect your plants for hornworms, look for aphids too.

Back to the Tomato Hornworm

A morning and evening once-over will go a long way toward ensuring your plants don’t fall victim to this remorseless invader. Look for the matching green caterpillar lying nearly invisible along the stem or underside of the leaf. You’ll want to rid your plant of the hornworm asap. We’ll get into how to get rid of tomato hornworms a little later in this article.

All in the Family

The tomato hornworm isn’t alone, however. Its cousin, the Tobacco hornworm (Manduca sexta), wreaks similar havoc on its plant of choice, tobacco. Both these caterpillars are drawn to plants in the nightshade family such as tomatoes, eggplants, potatoes, tobacco, and green peppers.

The hornworms pupate underground over the winter months and emerge as moths in the spring to mate. Like many insects, after breeding, female tomato worms lay eggs almost always on the underside of the leaf to help minimize their chance of detection by egg-eating insect predators.

There is a Difference in Hornworms

While quite similar in looks, the tomato and tobacco hornworms are distinguishable from one another if you know what to look for. The tobacco hornworm displays more elongated vertical white lines with a red colored hook adorning its tail while the tomato hornworm sports a set of white, ‘V-shaped’ markings along its sides and a black horn on its tail end. Their tail-end hooks are often mistakenly thought to be stingers but in truth, are harmless.

Interestingly, these worms are interchangeable when it comes to dining. You may find tobacco hornworms on a tomato plant and a tomato worm on a tobacco plant. Both are terribly destructive and can devastate a crop if undetected for any length of time. After the eggs hatch the caterpillars spend the next four weeks feeding on your plants until reaching maturity, at which time the tomato worms drop back into the ground to pupate and the life cycle is repeated.

I See You... or Do I?

Hornworms are masters of camouflage. These vine colored caterpillars, found living and dining on tomato plants, aren’t easy to spot at a glance. Their near-perfect color match of your tomato vines is an excellent disguise. It is Nature doing some of her best cloaking. You really have to look carefully to see them. Once you do, it’s almost an aha moment. Now you know what to look for!

Give Your Plants the Onceover

Look your plants over carefully. Where leaves begin to droop or vines appear stripped of their leaves in areas, it’s a safe bet you have, or have had, hornworms eating on your plant. Take the time to look your plants over thoroughly. These worms can defoliate a plant in short order. Careful scrutiny can make the difference between havoc or harvest.

Now You See Me

I see one… now what? Now that you’ve spotted one and know what to look for, it’s time to take action. The gardener has several options available to them when it comes to ridding the garden of hornworms.

How to Get Rid of Hornworms

No one wants hornworms anywhere near their garden but many gardeners don’t want to resort to chemical warfare to eliminate them either. There are several natural methods of getting rid of hornworms that do not employ the use man-made pesticides or insecticides. For the more natural gardener, the following options make the most sense.

Hand to Hand Combat

The fastest and most natural way to rid your plant(s) of tomato hornworms is pretty much the hands-on/bugs-off approach. It is as simple as it sounds. You manually pluck the hornworm off your plants with gloved fingers or by using a pair of tweezers to remove him. Once removed, you can drop the little invader into a container of water which will drown him, or simply drop him to the ground and do your best Bigfoot impression.

 

 

To deter these and other invaders from ruining your tomatoes, you can make up a home-made recipe consisting of dish soap, water, and cayenne pepper. There is no set portion, just make the water somewhat soapy (you can use a natural and/or biodegradable soap) and sprinkle in some cayenne powder. Spray your plants down with this concoction. Moths are repelled by the smell and taste of this cayenne cocktail and will go elsewhere for their meal. Likewise, other harmful insects will look for another plant upon which to lay their eggs.

This works on more garden pests than just tomato worms and this tincture won’t hurt your plants but will dissuade hornworms and other uninvited diners from dropping in. Should it rain or get washed off, simply reapply.

TIP

Preventive measures can be of great help when it comes to fighting the tomato worm. Sheets of plastic liner placed flat on your garden floor will help prevent the moth larvae from breaking through the ground and heading straight for your tomato plants for breakfast.

This is a Good Thing to See

Beneficial Insects

Should you spot a hornworm with a bevy of white eggs attached to its back, leave it alone. Those eggs are not the eggs of the hornworm but of a parasitic wasp (Braconid Wasp) that lay their eggs on the back of the caterpillar. When those eggs hatch it’s role reversal. The wasp larvae become the diners and the hornworms become the meal. These beneficial insects are a blessing to have in the garden, although the worms may not feel the same way.

Additionally, you will soon have a little army of garden-friendly wasps (harmless to people) that feed on the tomato hornworm and the tobacco hornworm and through their life cycle will grow up to lay their eggs on future trespassers.

But Wait! There’s More!

The parasitic wasp is only one of many beneficial insects proven to be a friend in the garden. Moreover, insect vs insect is one of the most natural and effective ways to rid your dominion of tomato hornworms and tobacco hornworms along with many others that either eat your plants or lay eggs on them.

If you’d like to learn more about using nature to fight nature in your garden, simply follow this handy link to [Ben: I thought perhaps insert a relevant topic from the Natural Pest Control listings here (Lady Bugs?). If not, just delete this section]

A Little Help From Our Fine Feathered Friends

Additionally, if your neck of the woods includes birds such as robins and mockingbirds, you’re in luck. As they spend a lot of time on the ground, those particular birds are quite good at spotting hornworms and removing them. Still, always look for signs of hornworm damage with your own bird’s eye view.

But even if you do have these birds around your plot, don’t rely solely on them to get rid of tomato hornworms. They have plenty of other insects upon which they feed. Just by them being around, however, does afford you one more weapon to help get rid of tomato hornworms in the garden.

More Natural Pest Control

Other methods used to fight these worms include the use of chemicals – but good ones, designed specifically to fight hornworms. For a serious infestation, you may need to bring out the big guns. Bacillus thuringiensis or BT. BT is a soil-dwelling bacterium used to control hornworms. Bacillus thuringiensis can be readily purchased in your favorite garden center.

Kills the Worms and Not Your Plants

Totally harmless to vegetation, this natural solution is sprayed directly onto tomato plants. When hornworms consume a leaf treated with BT, the worms loses their appetite and literally starve to death. Begin treatment at the first sign of these invading worms.

The End and the Beginning

So there you have it! You now know not only what to look for on your tomato plants but how to treat the problem of tomato hornworms naturally and effectively should the need arise. Preventive measures go a long way toward a happy and healthy tomato harvest. You can now go from having green worms to having a green thumb with these useful tips from us and a little help from Mother Nature.

Happy Harvest!