Have your ever noticed small holes in the leaves, fruit and stems of tomatoes, peppers and eggplants? Are small brown droppings present on your garden plants? If so, you may be observing the presence of the tomato hornworm.
However, as frustrating as an infestation can be, there are a number of steps you can take to control and eliminate hornworms in your garden. We’ve prepared this guide on hornworms and their life cycle to help you learn how to get rid of them. With a little hard work and the careful use of insect-killing products approved for organic gardening along with the use of beneficial insects, you can repel and prevent the tomato hornworm from eating your precious fruit before you do.
Thwarting a Tomato Caterpillar Invasion
Eliminating this pesky insect can be difficult. However, there are various simple tomato hornworm control techniques that can help you tackle your caterpillar problem.
Your first step should include thoroughly tilling soil at the beginning and end of the gardening season to destroy the larvae. Use a root-tiller, especially during the nongrowing season. Larvae are quite large and spend their winters buried just below the surface while in their pupal stage. A good tilling will break up the pupas and prevent them from emerging next summer.
There are also a number of beneficial insects that eat hornworms while avoiding your plants. Braconid wasps, ladybugs and lacewings either destroy or feed on the eggs of hornworms, helping to control the population. Make sure to release these beneficial insects before the infestation is full-blown, since they are better for preventing a population from growing than destroying one that already exists.
However, sometimes the best approach is more hands-on. Especially if your garden is small, you can pick the tomato worms out of the soil by hand; they are completely harmless and won’t bite or sting. They are large and easy to grab. Just drop them into a pail of soapy water to destroy them. Because of their green color, they can easily blend in when sitting on a stem or a leaf. If you are having trouble finding them, just spray the area with water, and the caterpillars with begin to squirm.
The Best Form of Tomato Worm Control
While there are several steps you can take before turning to insect-killing products, sometimes doing so is the wisest choice, especially if the size of your garden makes manual removal inefficient. A product such as Safer® Brand Garden Dust can quickly and easily be used for tomato hornworm control. The active ingredient in Safer® Brand Garden Dust is bacillus thuringiensis, a naturally occurring substance that causes the worm to stop feeding in a matter of hours when ingested. The tomato caterpillar typically dies in just a few days.
Safer® Brand Garden Dust is an OMRI Listed® product, meaning it contains ingredients that are approved for use in organic gardening practices.
For best results in controlling tomato worms, thoroughly cover plant leaves with the product and reapply every seven to 10 days or as often as necessary. Since caterpillars don’t hatch all at once, you can destroy an entire infestation only to find that they have reappeared in a week or so. Just apply 2 to 3 ounces for every 50 feet of garden every time caterpillars appear.
What Is a Tomato Hornworm?
The tomato hornworm caterpillar, or manduca quinquemaculata, is a greenish caterpillar measuring about 4 ½ inches long. It has a spike or horn on its tail, giving this insect pest its name. It can be found throughout North America and has long wreaked havoc on tomato, pepper, tobacco, potato and eggplant crops. They especially love eating leaves and stems, although they will sometimes feed on the fruit of plants as well.
Even though they are large, they are also the color of the leaves they feed upon, providing them with excellent camouflage. White stripes can be found across their bodies, finishing with their signature red horn at the end.
Eventually, these caterpillars become moths, called the hawk or sphinx moth, which are brown or gray with white zigzags across their wings. The larval stage of the tomato hornworm is the only destructive stage since it feeds on the leaves, fruit and stems of plants.
Keep in mind that if the moths are present, they will lay eggs which will eventually grow into plant-hungry larvae. So if you see this insect in any of its three stages, you should consider taking appropriate steps for controlling the population.
In addition to tomato hornworms, tobacco hornworms are also often found in North American gardens. The tobacco hornworm, a relative of the tomato hornworm, is found on tobacco plants throughout North America. Since this larvae has similar eating habits, the control methods are also much the same.
Tomato Hornworm Life Cycle
Adult moths will mate and lay eggs in late spring. Their eggs are small, green spheres, and can usually be found on the undersides of the same leaves they will someday eat. The eggs hatch in about six to eight days. After that, the larvae will go through development in stages that last up to four weeks, which includes the ravenous feeding that can cause such destruction within your garden.
After a summer of getting their fill, they will go below ground to spend the winter in the pupal stage, emerging in June or July of the following year as adult tomato hornworm moths, ready to begin the cycle over again.
This is why you need to interrupt the tomato hornworm life cycle one way or another. Whether you destroy the pupas with a root-tiller or kill the larvae with an insect-killing product, by interrupting the cycle, you will prevent future infestations of hornworms.
Tomato Hornworms’ Habitat
Tomato hornworms can be found on tomatoes, peppers, eggplants and other members of the nightshade family. In other words, if you live anywhere in North America where you can plant a vegetable garden, you run the risk of hosting hornworms.
In fact, hornworms need gardens, with their broad leaves and soft soil, in order to survive. Because they lay their eggs, feed and breed around vegetable plants, they are just as tenacious in protecting their claim to your garden as you are about eliminating them.
This is what makes them so difficult to eliminate. They aren’t going to be discouraged and look for greener pastures elsewhere. If only a handful remain, they will quickly breed and return to their previous numbers.
Considering how inviting your garden or field is to these pests, you have to do everything you can to eliminate the entire population before they eliminate your hard work.
Symptoms of Tomato Hornworm Damage
Holes in the leaves, fruit and stems of tomatoes, peppers and eggplants are typically the first thing you’ll notice in your garden, and this likely indicates the presence of the tomato hornworm. A few holes in your plants may not seem like a big deal, but if this minor damage is allowed to progress, it will soon destroy your plants and ruin your crop.
With its large size, the tomato hornworm might be visible on plants. In fact, the first time you see one of these large insects, it can be quite shocking. Obviously, if you find a caterpillar on your plants, you know the hornworm is the culprit. However, its coloring does camouflage it very well, so it can often go unnoticed despite its size.
If you find the telltale holes but are still unsure if you have a true hornworm infestation, the next step is to look for hornworm droppings. Clustered tan or brown droppings may be seen on plant leaves and parts. Often you can find a resting hornworm right above where you find their waste.
Once you find proof of hornworm damage, you can be confident that you are hosting an entire hornworm party. If there is one larvae or one patch of droppings, eggs and other larvae are sure to be in the garden as well. If you see symptoms, it’s time to start treating your garden or fields for hornworm infestation.
Results of Tomato Hornworm Infestation
Hornworms are voracious eaters. If left undisturbed on a plant, hornworms can completely defoliate your garden vegetables in just a few days. With the larvae eating the leaves and new stems of plantings, the planting may die, although plants can typically recover if the hornworms are removed early.
However, even if the plant survives the initial leaf feast, if you don’t remove the larvae, they will move on to other, more prized fruits of your garden. Later in the season, the tomato hornworm feasts on the actual tomatoes, peppers and eggplants, making your fruit or vegetables unmarketable and unappetizing.
If you’re farming with the goal of making money, a hornworm infestation can hit your pocket hard. Even if you have a small garden, hornworms can erase hours of work and spoil the joys of a homegrown vegetable on your family table.
How to get rid of Tomato Hornworms
As we already discussed, there are a number of insect-control products that can assist you in your quest of taking back your garden from hornworm invaders.
With so many products on the market, it is tempting to purchase the first one you see on the shelf in your local garden center. However, not all products are created equal. Chemicals have a lasting impact on the environment, so you should know what’s in your insect control products and how they work.
With that in mind, here is a quick rundown on a few organic and effective options.
What OMRI® Compliant Gardening Products Are Out There?
Products such as Safer® Brand Garden Dust, Safer® Brand Tomato & Vegetable Insect Killer and Safer® Brand Caterpillar Killer II with B.T. Concentrate are approved for organic gardening and can be used for effective tomato hornworm control.
Safer® Brand Garden Dust provides an effective method of eliminating tomato hornworms in your garden or field without environmental concerns or potential harm to wildlife and beneficial insects when used as directed.
Insecticides containing B.T., such as Safer® Brand Caterpillar Killer II with B.T. Concentrate, can also be an effective method of controlling the hornworm.
How Do These Products Work to Control Tomato Hornworms?
Safer® Brand Garden Dust kills hornworm larvae, thereby preventing further damage. When the worm ingests the B.T., it works as a gut rot poison that makes the worm stop feeding. The tomato hornworm will stop feeding immediately and die within days from malnutrition.
Safer® Brand Caterpillar Killer II with B.T works in much the same way. When a hornworm eats the treated foliage, it will immediately stop eating and die shortly thereafter.
B.T. usually comes in a dust or concentrate and kills a variety of caterpillars and worms, including the destructive hornworm.
Sprays containing pyrethrin such as Safer® Brand Tomato and Vegetable Insect Killer paralyze the insects, resulting in their death. Since they are OMRI Listed®, you know the ingredients are approved for use in organic gardening.
As with any insect-control product, it is recommended with any pesticide to test plants for sensitivity to the product. Spray a small section of the plant in an inconspicuous area and wait 24 hours before full coverage.
Safer® Brand offers a variety of tomato hornworm control products to help control and eliminate this garden pest and revive your plants. Please check out our tomato hornworm-control products for more details, including their chemical contents.
When Should I Use These Products?
As with any gardening product, when you apply affects how well they work. With that in mind, here is a quick rundown on when to use insect-control products so that you can quickly get your hornworm infestation under control.
Any product with B.T. is best applied when it is a cooler time of day, preferably later in the afternoon or early in the evening, since the product breaks down in sunlight and heat. A cloudy day is also a perfect time to apply the product.
When applying pyrethrins to infected plants, do not spray plants in the peak of the day or when temperatures exceed 90° F.
As with any product, carefully read and follow all directions on the product labeling for safe and effective application.
Why Choose a Pest Solution?
Thankfully, many people are starting to realize that products that are compliant for use in organic production are the best solutions available. Why exactly are these products preferred? These solutions break down quickly into their natural elements. They are preferable to chemical pesticides that leave residuals where they are sprayed, causing long-term detrimental effects on the environment.
Plus, if you’re using the wrong insect-control products on produce, these chemicals can make their way into your food, eventually reaching your home and family. You put your love and sweat into your garden because you want to put great food on the tables of your family and whoever else eats your produce. So you want to choose a product that befits the fruits of your labor.
Natural Predators of the Tomato Hornworm
In addition to natural products, natural predators and beneficial insects can effectively control the hornworm population in your garden or fields. How do these predators work and how can you be sure they aren’t just as harmful as the caterpillars you are trying to kill? Here is a quick rundown on natural beneficial insects that you can employ to keep your garden pest-free.
What Insects Are Beneficial?
Parasitic braconid and trichogramma wasps, ladybugs and green lacewings are beneficial insects that help to control tomato hornworm problems. They can be attracted naturally to your cornfield or garden area where your vegetables are planted, and there are some companies that raise these insects and sell them to consumers.
How Do These Insects Work?
Different beneficial insects work in different ways. On the one hand, the parasitic wasp lays its eggs inside the tomato hornworm's egg, destroying the hornworm egg in the process. The presence of parasitic wasps have shown success rates of more than 50 percent in eliminating hornworm populations.
On the other hand, upon hatching, the green lacewing larvae will eat the larvae of the tomato hornworm. They eat hornworms and their eggs just as voraciously as hornworms eat your plants. Ladybugs feed much the same way.
Either way, whether they are eating or destroying hornworm eggs, the presence of beneficial insects will help interrupt the life cycle of the hornworm and destroy the population.
How Do I Get Beneficial Insects Into My Garden?
There are a number of ways to invite these beneficial insects into your garden. Planting pollen and nectar-bearing flora near the tomatoes and peppers may attract these beneficial predators. If trying to attract them doesn't work, they can also be purchased from companies who raise them. These are the types of bugs you will be glad to see while you are gardening, as they work hard to keep your plants hornworm free.
When Should I Employ These Insects?
Plant the pollen or nectar-producing flora as soon as possible according to the temperature of your area. Most local greenhouses and garden centers can help you determine the right planting time.
If you are purchasing insects, there are a few basic guidelines for their release. Ladybugs should be released in the evening. Lacewing larvae should be spread immediately after you have acquired them. Wasps should be released when you observe the presence of adult hornworm moths.
For more specific instructions, contact a company that raises beneficial insects to find out when they should be purchased and released for maximum hornworm control.
Why Should I Use a Natural Predator?
There is no more natural of an approach to hornworm control than employing a natural predator. These insects normally feed on hornworms without human intervention. By introducing them into your garden, you are helping Mother Nature do something she would do normally. They don’t contain any chemicals and are a healthy part of the ecosystem. Beneficial insects are an effective and guilt-free solution to your hornworm infestation.
The tomato hornworm and its cousin the tobacco hornworm are pests that are as destructive as they are annoying. In a matter of days, these moth larvae can completely destroy a plant, undermining the hours of work that you’ve put into your garden or field. With their camouflaging color, they can often go undetected. However, if you can learn to recognize the signs – such as holes in the leaves of your plants or the sight of brown droppings on your foliage – you can begin to take the proper steps to take back your garden.
Tilling the soil and manually removing hornworms can destroy the life cycle of these pests, especially if you have a small garden where working with your hands is more manageable.
If you need a little more power, natural products are an effective solution for killing and eliminating the threat to your produce.
Hopefully this guide on how to get rid of tomato hornworms has helped you identify the damage these caterpillars cause and the best ways to address the problem. With these approaches, your garden will quickly recover from the damage caused by your unwanted guests.