You’ve waited all summer for that first luscious tomato to ripen only to discover that, almost overnight, something has been feasting on your tomato plants, stripping the stems bare and chomping holes in your nearly ripe fruit. The culprit? Most likely it’s the tomato hornworm (Manduca quinquemaculata), a plump, green caterpillar named for the threatening but harmless “horn” protruding from its tail.
What makes the tomato hornworm such a menacing garden pest is its ability to defoliate tomato plants in days. Although it prefers to munch on tomatoes, it will also happily feed on potatoes, eggplant, peppers, tobacco, and other plants in the nightshade family (Solanaceae).
The good news is that you can eradicate tomato hornworms, without resorting to chemical insecticides, by using a variety of natural control methods. Learning how to recognize the early signs of a hornworm infestation can also help you prevent these destructive creepy-crawlers from getting out of hand.
Caterpillars munching on the leaves and fruits of tomato plants can be incredibly frustrating for home gardeners These creepy crawlers seem to appear overnight and can quickly defoliate entire plants, leaving tomatoes exposed to sunscald While caterpillars are a natural part of the ecosystem, when they invade your vegetable garden, control measures are often needed.
In this article, we’ll cover the most common caterpillar species found on tomatoes, the damage they cause, and effective organic and chemical treatment options. With a little knowledge and persistence, you can protect your tomatoes from these voracious pests.
Identifying Tomato Caterpillars
The first step in caterpillar control is proper identification. There are around 15-20 species of caterpillars that are known tomato pests. Here are some of the most likely culprits:
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Tomato hornworm – Large green caterpillar with white V-shaped markings on sides and a black horn on rear.
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Tobacco hornworm – Closely related to tomato hornworm but has red horn and slightly different white markings,
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Cutworms – Plump, smooth caterpillars that hide in soil and chew stems at base of plants.
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Armyworms – Striped caterpillars in various colors that feed in groups and quickly defoliate plants.
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Tomato fruitworm – Also called corn earworm, varies in color but known for boring into fruits.
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Loopers – Inchworm-like caterpillars that clasp to leaves with suction cup feet as they feed.
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Pinworms – Tiny yellowish caterpillars that create silk tents on undersides of leaves.
Take note of the color patterns, markings, and behaviors of caterpillars on your plants. This will help you identify the exact species, which leads to more effective control.
Damage Caused by Tomato Caterpillars
Caterpillars go through multiple growth stages as they feed, increasing the amount of damage they cause over time. Here are some common problems caterpillars create:
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Skeletonized leaves from caterpillars eating leaf tissue between veins
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Irregular holes chewed in leaves
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Stems severed at base of plants from cutworm feeding
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Tunnels bored into tomatoes, especially by fruitworms
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Premature dropping of flowers and fruits
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Black frass (caterpillar poop) on leaves and fruits
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Quick defoliation of entire plants
Extensive feeding exposes fruits to sunscald and reduces the plant’s ability to ripen tomatoes. It also stresses the plant, making it more vulnerable to disease.
Organic Caterpillar Control Methods
For mild infestations, organic methods like the ones below can effectively manage caterpillars:
Handpicking – Inspect under leaves and remove caterpillars by hand daily. Drop them in soapy water.
Row covers – Cover plants with fabric row cover to create a physical barrier.
Natural predators – Attract beneficial insects like wasps, ladybugs, lacewings, and birds.
Companion planting – Interplant tomatoes with basil, onions, garlic, and marigolds to repel pests.
Organic pesticides – Apply Bacillus thuringiensis (Bt) and spinosad for caterpillar-specific control.
Diatomaceous earth – Sprinkle this abrasive dust on leaves to shred caterpillars’ bodies.
Neem oil – Made from neem seeds, it smothers small soft-bodied insects when applied as a spray.
For heavy infestations, combination treatments are often needed. Handpick larger caterpillars while applying organic pesticides to kill eggs and tiny young larvae.
When to Use Insecticides
If organic options aren’t containing the caterpillars, insecticides are a last resort. Insecticidal soaps and botanical insecticides like pyrethrins can provide quick knockdown of caterpillars.
Some key points for using insecticides responsibly:
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Read and follow all label directions
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Spray early before populations explode
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Target small larvae for best results
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Avoid spraying during bloom to protect pollinators
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Rotate chemical classes to prevent resistance
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Limit use to spot treatments instead of whole plants
Repeated applications are often needed as new eggs continue to hatch. Always follow pre-harvest intervals on labels before eating treated tomatoes.
Preventing Future Caterpillar Attacks
While controlling current pests is important, prevention is ideal for dealing with caterpillars over the long-term:
Time planting – Avoid peak egg-laying times by delaying planting.
Weed control – Eliminate caterpillar host plants around the garden.
Sanitation – Promptly remove and destroy infested plants and fruits.
Crop rotation – Don’t plant tomatoes in the same spot as last year.
Row covers – Cover plants early before pests arrive.
Scouting – Inspect plants frequently to detect caterpillars early.
Beneficial insects – Choose flowers that attract caterpillar predators.
Resistant varieties – Some new tomato varieties have caterpillar resistance.
By integrating multiple tactics, you can minimize damage from tomato caterpillars and enjoy an abundant harvest. Just remember to be vigilant about scouting for these sneaky pests. With early detection and quick action, you can stay one step ahead of hungry caterpillars in your garden.
INSPECT YOUR PLANTS REGULARLY
Tomato hornworms are typically easy to control in the garden if you regularly monitor your plants for the presence of the caterpillars as well as the adult moths (called five-spotted hawk moths) that bring them into being.
Although the caterpillars are large (typically 3 to 5 inches long), they are well-camouflaged and blend in almost invisibly with the color of the foliage. They typically become active in early to midsummer, just as tomato plants are reaching full size. You can identify them by the V-shaped white markings on each side of their bodies and their distinctive black horns. But often the first clues that hornworms are present are chewing damage and dark green droppings (frass) deposited on the leaves.
Watch this short video from Erin, The Impatient Gardener, to see how to look for them at night.
Adult moths can be recognized by their mottled gray-brown color, impressive 4- to 5-inch wingspan, and yellow spots on each side of their abdomens. You’ll usually see them after dusk, hovering like nocturnal hummingbirds to sip nectar from flowers. In late spring, be on the lookout for the female moth’s small green eggs, which she will lay on the host plant’s leaves. Once the hornworms hatch, your plants are at the mercy of their insatiable appetites for up to 4 weeks.
Five-spotted hawk moth. Photo by: Sari ONeal / Shutterstock
Tip: The tomato hornworm is sometimes confused with the tobacco hornworm (Manduca sexta), a close cousin commonly found in the southeastern U.S. that also targets plants in the nightshade family. Although these caterpillars are similar in appearance, the horn of the tobacco hornworm is reddish in color and the white markings on the body are diagonal rather than V-shaped. No matter which type of hornworm you’re dealing with, the damage they can do to your plants is equally devastating.
ATTRACT BRACONID WASPS TO YOUR GARDEN
Tomato hornworm with braconid wasp eggs. Photo by: Stephen Bonk / Shutterstock
A natural enemy of the tomato hornworm is the braconid wasp (Cotesia congregatus), a small, non-stinging parasitic wasp that deposits its eggs just under the skin of soft-bodied caterpillars. The eggs hatch and the larvae feed on the hornworm until they are ready to pupate. After the larvae break through the skin, they spin cocoons on the hornworm’s back that look like tiny grains of puffed rice.
If you’re handpicking tomato hornworms and notice one covered with these cocoons, leave it be or move it to a sacrificial plant where it can live out its remaining days. The weakened worm can no longer damage your plants, and the cocoons will give birth to a new generation of braconid wasps. In addition to tomato hornworms, this beneficial insect will also prey on tobacco hornworms, cabbage worms, and other garden pests.
Tip: To encourage braconid wasps to visit your garden, grow plants that produce an abundance of small, nectar-rich flowers, such as sweet alyssum, chamomile, yarrow, and catmint. When allowed to flower, dill, fennel, and other members of the carrot family also attract these garden allies.
Problem Solved! Tomato Caterpillar Control. Organic and 100% Effective.
FAQ
How do I get rid of caterpillars on my tomato plants?
PICK OFF THE CATERPILLARS BY HAND
Once you spot tomato hornworms, often the best way to deal with them, especially if their numbers are small, is to pick them off your plants by hand and drown them in a pail of soapy water.
Should I remove hornworms from tomato plants?
“If you spot a hornworm on your tomato plant, my recommendation would be to promptly remove them by hand,” says Kantor.Jan 17, 2024
Can a tomato plant recover from hornworm damage?
HU, give your plant some time to recover if possible. I get hornworm damage every year on my tomato plants. The leaves will grow back and the plant will continue to grow. It will take alittle time for the plant to produce flowers again. Just keep watch for any new hornworms to avoid more damage.