Tomato Hornworms and Parasitic Wasps

Gardening is always fun. Having your own garden and growing your favorite vegetable is so much fun. But gardening is not that easy. One needs to take too much care and responsibility to protect their gardens.

Gardens are always at high risk of getting attacked by pests and insects that can ruin the entire plantation. So, one needs to be very alert while gardening.

People practicing gardening also witness attacks of tomato hornworms that tend to destroy the entire plantation along the vegetables planted. They generally attack and serve on tomatoes, potatoes, and eggplants.

But what exactly are tomato hornworms? Where do they come from? And how do they defoliate the entire plantation? Isn’t there anything that can be done to prevent the damage caused by them?

To all your such problems, we have our solutions ready. We know that you cannot bear seeing your garden getting destroyed and hence we are here. By the end of the article, you will be well known with tomato hornworms and will have effective ways to prevent and fight their attacks.

What Are Tomato Hornworms? 

What Are Tomato Hornworms

Tomato Hornworms (Manduca quinquemaculata) are common garden pests that are found usually surviving on tomato plants. They basically feed on plants in the Solanaceae family which includes tomatoes, peppers, eggplants, and potatoes.

The adult tomato hornworms are usually larger and are robust-bodied moths. They are commonly known as hawk moth or sphinx moth. The adult hornworms feed on the nectars of the flowers.

These tomato hornworms are widely found in North America. One can find tomato hornworms around northern Mexico to the southernmost region of Canada. But at places, tomato hornworms are rare and are replaced by tobacco hornworms. They kind of look similar and often confuse people but if you notice minutely, you could easily differentiate between them.

Tomato Hornworms and Tobacco Hornworms have different morphological features that can be easily used to differentiate between them. Tomato hornworms have V-shaped yellow-white markings on the body while Tobacco hornworms have white diagonal lines.

Moreover, the horn which is a small protrusion on the final abdominal segment of the caterpillar of the tomato hornworm is black and the tobacco hornworm is reddish in color.

Click on the link below to understand Tomato Hornworms better: –

Identifying Tomato Hornworms

A lot of insects look the same. The varieties of insects even make it harder to understand and identify them. So, it is very important to study them in detail to identify the correct insect. Some insects prove to be useful while others prove to be harmful. So, if you could identify the correct ones only then you could effectively do your gardening.

Tomato Hornworms have already been a mess creator to your garden, so it is helpful to identify them to fight them. Below given are a few points that will help you to identify tomato hornworms.

  1. Tomato Hornworms are among the largest caterpillars in Minnesota and can measure up to 3-4 inches.
  2. When tomato hornworms are small, they are usually yellow to white in color.
  3. Large caterpillars have 8 white V-shaped marks on them.
  4. They also have a horn on the last abdominal segment.

Understanding Adult Moths?

Adult moths are large. They have a heavy body with narrow front wings. There are yellow spots on the sides of its abdomen. The wing of the adult moth spreads to around 4-5 inches. Also, the hindwings alternately have light and dark bands.

The Life Cycle of Tomato Hornworms

Tomato Hornworms survive as Pupae in winters and turn into adult moths in spring. Later after mating, females deposit oval green eggs on lower and upper leaf surfaces. Then caterpillars hatch and begin to feed. They are fully grown in three to four weeks and when the caterpillars are matured, they drop off plants and burrow into the soil to transform into pupae.

Usually, moths begin their second generation in two weeks during the mid-summer. The second-generation moths deposit eggs on the host plants such as tomato, eggplant, and others. The caterpillars feed until the late summers or even fall early and then they pupate and the papae remain in the soil throughout winter.

Refer to the link below to learn in detail about the life cycle of tomato hornworms.

Parasitic Wasps:

Parasitic Wasps

Parasitic Wasps act as the savior for gardeners and farmers. They attack and kill many of the insect pests. These wasps live a part of their lives as parasites inside other insects. They comprise one of the largest insect groups.

One can find hundreds of different species that vary in shape, size, and color. But mostly their shape spreads between small to medium size. They are generally brown or black in color, while the larvae are usually cream-colored.

Click the link below to understand parasitic wasps in detail.

Uses of Parasitic Wasps

Uses of Parasitic Wasps

Parasitic Wasps work great in keeping your garden safe from other insects and pests. It is very effective in keeping garden pests in control. Sometimes when you spray insecticides in your garden hoping for an effective outcome but ends up making the situation even worse. That is because you killed the parasitic wasps too.

Parasitic Wasps effectively control aphids, scales, whiteflies, sawfly larvae, ants, leaf miners, and several types of caterpillars. Hence, parasitic wasps can be a great asset while practicing gardening.

Tomato Hornworms & Parasitic Wasps

Tomato hornworms (Manduca quinquemaculata) are a real threat to your tomato gardens. These caterpillars can quickly damage the entire tomato plant. So, if in case you identify them in your gardens or plants just pick them up and throw them away that is the only way to get rid of them.

The female parasitic wasp lays her eggs under the skin of the hornworms. As the eggs under the skin hatch, the larvae begin to serve on the hornworm. The larvae eat their way out of these caterpillars and spin them. Eventually, then adult wasps will emerge as cocoons and the hornworm it survived on will die.

Damage Caused by Tomato Hornworms 

Damage Caused by Tomato Hornworms

Tomato hornworms cause major damage to your garden. They defoliate your planted vegetables like tomatoes, potatoes, eggplants, and pepper. Many weeds serve as an alternate host.

They also start feeding on the upper parts of the leaves. Older tomato hornworms can damage various leaves and sometimes also fruits. The larger they become the more their capacity begins to increase. Hence the risk of getting your plants defoliated increases.

The fruits that are fed by the tomato hornworms do not grow properly further, and thus also have no market value. Many caterpillars can destroy your garden to a great extent if not taken well care of.

Ways of Controlling Tomato Hornworms

Well, as we can already understand, the damage that hornworms cause is quite serious and requires quick action. One of the ways of dealing with them is to throw them out of your garden as soon as you see them. It means that one needs to be very attentive towards their gardening activities. Only then they could prevent their garden from getting worse by the attack of tomato hornworms.

But other than that, we also have few measures to fight their attack. Some of them are discussed below: –

  1. Usually, the very first effective way to fight tomato hornworm wasps is to strictly monitor your garden activities. Once you see it, just pick it up with your hand and throw it away.
  2. Bacillus thuringiensis (Bt) can be used to help in controlling the spread of tomato hornworm wasps. It is a biological insecticide widely available organic option for the control of caterpillars.
  3. Insecticidal Soaps are also a great idea that can effectively deal with tomato hornworms. The only condition is that it should come in direct contact with the tomato hornworms.
  4. Using Spinosad pesticide can also help you get rid of the tomato hornworms.

Preventive Measures from Tomato Hornworms

As we know, how severely tomato hornworms affect our plants and vegetables, therefore it is very important to take preventive measures to prevent our gardens. Below given are few measures that can help us prevent our garden from being affected by the attacks of tomato hornworms.

  1. Till your soil before and after the end of each gardening season. This will help you to destroy overwintering larvae. This activity has shown that it increases the mortality rate of insects by around 90%. So, this seems to be quite effective.
  2. Keep a few wasps in your garden. As we know that wasps serve on tomato hornworms and later eventually lead to the death of the hornworms. So, this can be very beneficial in preventing your garden from the attacks of tomato hornworms.
  3. Various other beneficial insects serve on tomato hornworms and can help you fight them. Ladybugs and Green Lacewings are few effective names.
  4. The other way of protecting your garden is using interplanting methods. You can interplant dill, marigold, or basil and can protect your garden from getting affected.
  5. Remove weeds so that the number of sites where warms can lay eggs reduces.

Refer to the below link to get more detailed information on managing tomato hornworms: –


We understand that your garden is very dear to you, and such attacks by tomato hornworms or other insects just upset you. But do not worry, these attacks can be overcome by some attentive activities and measures that we studied in the above article.

Your garden is your responsibility. Pests and insects are always going to make their homes inside. Some will be useful while some will be harmful. There is nothing to worry about. It can always be overcome by responsive efforts and measures.

We hope that the measures and guides that we provided in this article help you get rid of your tomato hornworms in the garden. And then finally you could feel relieved.

Hope to see and hear stories of your happy garden without tomato hornworms. Happy gardening.

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