How to Stop Tomato Hornworms from Harming Your Tomato Plants

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Tomatoes are a beloved addition to gardens across the United States. Their juicy red fruits are a staple in salads, sandwiches, and sauces. However, there’s a tiny but voracious enemy lurking in many gardens: the tomato hornworm. These green caterpillars may appear harmless, but they can completely defoliate a tomato plant in just a day or two. In this article, we’ll explore what hornworms are, the two types commonly found in States, how to spot them, and most importantly, how to get rid of them.

What are Hornworms?

Hornworms are large caterpillars that belong to the Sphinx moth family. They are named for the distinctive “horn” or protrusion on their rear end. Despite their intimidating appearance, hornworms are pretty much harmless – unless you’re a tomato plant. These pests have a particular affinity for tomato leaves and can quickly strip a plant of its foliage, hindering its ability to produce fruit.

Two Common Types of Hornworms:

In the United States, two types of hornworms are commonly encountered by gardeners: the Tomato Hornworm and the Tobacco Hornworm. These caterpillars are often mistaken for one another due to their similar appearance.

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Tomato Hornworm:

Color: Bright green with white diagonal stripes.

Horn: Orange or red.

Feeding Habits: Primarily targets tomato plants but may also attack other solanaceous plants like peppers and eggplants.

Geographic Range: Found throughout North America.

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Tobacco Hornworm:

Color: Bright green with white diagonal stripes.

Horn: Black.

Feeding Habits: Prefers tobacco plants but may also infest tomatoes, peppers, and potatoes.

Geographic Range: Widespread across North America.

How to Spot Them:

Identifying hornworms can be a bit tricky, but paying close attention to your tomato plants can help you spot them early. Look for the following signs:

Defoliation: Check for missing leaves or stems with no foliage.

Large Green Caterpillars: Hornworms can grow up to 4 inches long, making them easy to spot.

Dark Fecal Droppings: Look for small, dark pellets near the caterpillars.

Getting Rid of Hornworms:

Enlist the Help of Other Bugs:

Braconid Wasps: These tiny parasitoid wasps lay their eggs on hornworms, ultimately killing them. Encourage their presence by planting nectar-rich flowers.

Ladybugs and Green Lacewings: These beneficial insects feed on hornworm eggs and small larvae.

Attract Birds: Birds like robins and sparrows are natural predators of hornworms. Provide birdhouses or bird feeders to attract them to your garden.

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Hand-Picking: Wear gloves and inspect your tomato plants daily. Carefully pluck hornworms off and relocate them away from your garden.

Tilling the Soil:

Tilling the soil in the fall and spring disrupts the life cycle of many overwintering pests, including hornworms. This can reduce their population in your garden.

Tomato hornworms may be a menace to your tomato plants, but with vigilance and some natural allies, you can keep them in check. By identifying these caterpillars early, employing beneficial insects, attracting birds, and practicing good garden hygiene, you can protect your beloved tomato crop and enjoy a bountiful harvest.