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Tomato Hornworm

Tomato Hornworm

Manduca quinquemaculata

Insectalso: Tobacco hornworm, Hornworm

A huge green caterpillar, up to four inches long, that can strip a tomato plant of its leaves seemingly overnight. Despite its size it is a master of camouflage, so the chewed, bare stems and dark droppings usually give it away before you ever spot the caterpillar.

🔎 How to spot it

A plump, soft green caterpillar reaching about four inches, marked with a row of white V-shaped stripes along each side and a single curved horn at the tail end. The tomato hornworm has a dark horn and V-marks; the near-identical tobacco hornworm has a red horn and straight white stripes. Look for whole leaves and stems eaten down to bare stalks near the top of the plant, scattered dark green-black droppings (frass) on lower leaves, and chew marks on green fruit. The adult is a large, fast-flying gray-brown sphinx or hawk moth.

🥀 Damage it causes

The caterpillars chew leaves and can completely defoliate a plant, and they also gouge holes in green fruit. The largest caterpillar stage eats nearly as much as all the earlier stages combined, so a few big hornworms do most of the damage. Hosts are tomato plus other nightshades: pepper, eggplant, and potato.

🛡️ Prevent it

Till the soil after harvest to destroy the pupae that overwinter a few inches down, and rotate nightshade crops to a new spot each year. Plant flowers and herbs that draw in parasitic wasps, the hornworm main natural enemy. Scout plants every few days through summer so you catch larvae while they are still small.

🧯 If it is already here

Handpick the caterpillars and drop them in soapy water; on a small planting this alone is very effective. Hunt at dusk or with a blacklight, when they are easier to spot. For young larvae, the organic sprays Bacillus thuringiensis (Bt) or spinosad work well. If you find a hornworm studded with rows of white rice-like cocoons, leave it in place: it has been parasitized by braconid wasps that will hatch out and attack the next generation.

💡 Good to know

Hornworms blend in so well that the droppings and stripped stems are usually easier to find than the caterpillar itself. They overwinter as dark, spindle-shaped pupae in the soil and emerge as moths in spring, often producing two generations a season. The braconid wasp Cotesia congregata is a key ally, with a single hornworm sometimes hosting dozens of wasp larvae.

🌱 Plants it attacks

74 plants in the library can be attacked by this pest

Adirondack Blue PotatoAji Amarillo Pepper🥔All Blue PotatoAmish Paste TomatoAnaheim PepperBanana PepperBeauregard Sweet Potato🍅Beefmaster TomatoBetter Boy Tomato🍅Big Beef TomatoBig Boy TomatoBlack Beauty EggplantBlack Cherry TomatoBlack Krim TomatoBorage🍅Box Car Willie TomatoBrandywine TomatoCarolina Reaper PepperCayenne PepperCelebrity TomatoCherokee Purple TomatoCubanelle PepperEarly Girl TomatoFairy Tale EggplantFingerling PotatoFresno PepperGerman Butterball Potato🍅German Queen TomatoGhost PepperGreen Bell PepperGreen Zebra TomatoHabanero PepperHungarian Wax PepperIndigo Rose TomatoItalian EggplantJalapeño PepperJapanese EggplantJuliet Grape TomatoKellogg's Breakfast TomatoKennebec Potato🍅La Roma IV TomatoLemon Boy Tomato🍅Mortgage Lifter TomatoMr. Stripey TomatoNorland PotatoOrange Bell PepperPadrón PepperPimento PepperPineapple TomatoPoblano PepperPurple Bell Pepper🥔Purple Majesty PotatoPurple TomatilloRed Bell PepperRed Pontiac PotatoRoma Tomato🍆Rosa Bianca EggplantRusset Potato🍅Rutgers TomatoSan Marzano TomatoScotch Bonnet PepperSerrano PepperShishito Pepper🍅Striped German Tomato🍅Sungold Cherry TomatoSweet 100 Cherry TomatoSweet Banana PepperThai Chili Pepper🍅Tiny Tim Cherry TomatoToma Verde TomatilloTrinidad Scorpion PepperYellow Bell PepperYellow Pear TomatoYukon Gold Potato

For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.