Tomato Hornworms

How to Identify and Get Rid of Tomato Hornworms

Tomato Hornworm
Amanda Hill

Big, fat, and green! Here are tips on how to identify, control, and get rid of tomato hornworms in your garden.

What Are Hornworms?

If you’ve ever grown tomatoes, chances are good that you’ve dealt with these green caterpillar pests. There are two main garden pest species, tomato hornworms and tobacco hornworms, which can be found in most regions of the U.S. and in southern Canada. Both species can ruin your tomato crop in record time! They also feed on other plants in the Solanaceae (nightshade) family: eggplants, peppers, tobacco, and potatoes. They blend in quite easily with the green foliage and feed non-stop, creating spotty and chewed leaves and fruit.

Tomato (and tobacco) hornworms live according to the following life cycle:

  • In late spring, large adult moths lay eggs on the undersides of foliage, which will hatch within a week. The adult moths are easily recognizable; they’re commonly called sphinx or hummingbird moths.
  • Caterpillar larvae will hatch in late spring and feed for 4–6 weeks before creating a cocoon, overwintering in their pupal state in the soil. If the weather is warm enough, larvae may only burrow for as little as 2–3 weeks.
  • Moths will emerge in the spring, and will then lay eggs once again. More than one generation a year may be possible in warmer climates.

Tomato hornworm moth (female). Photo by Didier Descouens.
Tomato hornworm moth (female). Look out for the moths in late spring. Photo by Didier Descouens/Wikimedia Commons.

Identification

How to Identify Tomato Hornworms

Hornworms can be up to 5 inches long—which can be quite a shock when you first come across one! They do the most damage in the caterpillar—or larval—stage. They are pale green with white and black markings, plus a horn-like protrusion stemming from their rear. (Don’t worry, they aren’t able to sting or bite!) The caterpillar also has eight V-shaped stripes on its green body. Tomato hornworms come from a mottled brown-gray moth (see picture, above). 

    The larvae blend in really well with the plant greenery. Just get used to a daily patrol, looking for hornworm eggs and small caterpillars. Here are some cues of infestations:

    • Hornworms tend to start feeding from the top of the plant; look for chewed or missing leaves.
    • Look closely at the TOP of your tomato leaves for dark green or black droppings left by the larvae feeding on the leaves. Then look at the underside of leaves and you’ll likely find a hornworm.
    • Look for stems missing some leaves and wilted leaves hanging down. You may find white cocoons and their hornworm hosts nearby.

    Tomato Hornworm. Photo by Amanda Hill.
    Tomato hornworm

    Tomato vs. Tobacco Hornworms

    There are a few species of hornworms that inhabit North American gardens, including tomato hornworms (Manduca quinquemaculata) and tobacco hornworms (Manduca sexta). Both species feed on common garden plants like tomatoes, potatoes, peppers, and eggplants. Here’s how to tell which caterpillar is which:

    • Tobacco hornworms have parallel white stripes; tomato hornworms have white V–shaped markings.
    • Tobacco hornworms have black spots lining each of their stripes; tomato hornworms do not.
    • Tobacco hornworms have a red “horn” on their tail end; tomato hornworms have a black horn.

    tomato-worms-hornworms.jpg
    Can you tell which hornworm this is? (It’s a tobacco hornworm! Notice the white stripes with dotted black lines and a red “horn.”) 

    Tomato Hornworm Damage

    If you see leaves with large holes and severe defoliation, devoured flowers, and/or scarring on fruit surfaces, you might have tomato or tobacco hornworms. The fruit also may be damaged by sunscald because of the reduced foliage cover.

    Control and Prevention

    How to Get Rid of Tomato Hornworms

    • Handpicking is an excellent tactic for control if you have the time and patience, or a small garden. The caterpillars are not dangerous and can neither sting nor bite. If you are squeamish about crushing these large insects, drop them into soapy water instead (or feed them to your chickens, if you’ve got a flock).
    • If the hornworm population or the area of your garden is too large, insecticides can be effective, though they should be a last resort. You can use the organic pesticide Bt (Bacillus thuringiensis), which is a bacterium that acts as a stomach poison on some larval insects (but doesn’t harm other plants or animals). Bt must be ingested by the caterpillars to be effective, and it must be reapplied to plant foliage after rain. Please check with your local Cooperative Extension for a list of approved insecticides in your area.
    • Insecticidal soaps will also kill hornworms, but the pests need to come into direct contact with the substance.

    get-rid-of-hornworms.jpg
    A tobacco hornworm covered with parasitic wasp eggs. 

    How to Prevent Tomato Hornworms

    • Till soil at the beginning and end of each gardening season to destroy overwintering larvae. Tillage has shown to cause up to 90% mortality.
    • Keep wasps around; a number of species are beneficial insects which feed on hornworms and act as a biological control. You may see hormworms with parasitic wasp larvae attached, which look like grains of rice (see picture, above). These attacked hornworms will continue to feed for a little while, but will soon succumb to their hitchhikers, so it’s wise to leave them alone and let the wasps carry out their life cycle. Alternatively, remove infected hornworms and place them far away from your garden. This way, the wasps will still do their job, but the hornworm won’t continue to damage your crops. 
    • Other beneficial insect, like ladybugs and green lacewings, may feed on young hornworms or hornworm eggs.
    • To keep hornworms away from your tomato plants next year, try interplanting dill or basil; marigolds are also an excellent companion plant.

    See the Almanac Garden Pest and Disease Library for more information on common pest problems.

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    Reader Comments

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    Ridding cut worms from tomatoes

    Pest verses Plant
    I've been told by an agronomist that using "Sevin" on tomato plants for Hornworms will also eliminate the beneficial insects such as the pollinating bees and without bees we have no garden yield.
    Has anyone tried spraying plant with soap and water mixture?

    I found Hornworms on all my

    I found Hornworms on all my pepper plants, I am sure they have been munching on my strawberries as well. They are really harming my garden! Is there a way thatI can get rid of them through a "biological cycle" so to speak? Can I purchase these wasps as opposed to attempting to attract them? Or is picking/killing them and using BT the best option? Does Neem oil work? Is there a use for these worms? I would rather not mass murder creatures who are just trying to survive. (I know it sounds new-agey, but I would rather avoid that. Thank you!!!

    To clarify my earlier post I

    To clarify my earlier post I had a huge infestation of hornworms the first year. I did a lot of research on organic gardening during the off season. Borage is an herb and when planted in a cross section between the tomato plants it gives off a scent that Hornworns hate and will not go near. Ever since i started using this method I havent seen another worm on my plants. Hopefully it works for everyone else as well.

    I watched a red wasp hover

    I watched a red wasp hover in, bite a hornworm, about 3 inch long, fall about 3 leaves down and then eat the entire hornworm. The hornworm kinda melted into the wasp jaws.

    Since then I have left the two wasp nests alone out near the garden.

    I haven't really had much of a problem but those worms can really do damage in a short time. I am trying container potatoes this year, and 1 hornworm decimated one plant and half another before I found him. I find the droppings the dead give away. Sort of look like green mini croquet balls. Anyway after seeing these I started looking harder and sure enough a huge hornworm chowing down hiding in plain site. Similar to how the article describes finding one as shocking. Anyway killed it and placed it on the bird offering alter so he should be gone by this evening.

    Tomatoes are a total disappointment this year anyway so no big deal. Next year only heat loving varieties.

    Really appreciate your most

    Really appreciate your most informative article/response.. Just found my FIRST hornworm today, bagged him up and threw in in outside trash bin(and, YES, Very cold-hearted since I have a difficult time killing insects, rather go out of my way to spare and relocate them OUTSIDE!!! At any rate, 1/3 of my tomato plant was eaten..and Not by deer(due to tall fencing!!) LOVE the idea of offering the "Little Devils" to the birds though..LOL!!:):)

    When I found my first

    When I found my first hornworm, and double-checked it's identity using google images, I was intrigued by a photo of one being held in the mouth of a cardinal.
    So I put this 4" long caterpillar on the pavement near my bird feeder (so it would be easily seen). Sure enough, within about 10 minutes, a female cardinal took it. She dropped it twice, but she was determined. I don't like squishing, but I am happy to provide the cardinals with food.

    Be Careful With Neem Oil I

    Be Careful With Neem Oil
    I also read that neem oil work's well at getting rid of garden pest, but before you spray check the label, it will definitely kill your plants if used in area's where the weather is Hot. I have also tried hot sauce, garlic, dish soap with water and needless to say it was not effective in the least.
    I inspect my plants daily, and pick off the nasty hornworms by hand. It is the only thing that I have found that works the best so far.
    Happy Gardening to All of you.

    No, these are not the worms

    No, these are not the worms I'm talking about. I have never seen these before. I know what the hornworm looks like. These are BLACK WITH YELLOW STRIPES DOWN EACH SIDE.

    Just look up tomato hornworm

    Just look up tomato hornworm on Google and there are lots of pictures. I saw a worm just as you described

    It is a catawba worm.

    It is a catawba worm.

    I think the catapillar you

    I think the catapillar you may be describing is a milk weed catapillar..which will turn into a monarch butterfly...

    Last year was my first year

    Last year was my first year dealing with hornworms. I take pride in my tomatoes. From seed to harvest i trend my pants. It was a surprise that these large lazy worms were treating my hard work like a buffet. We also have chickens so we let them loose in the gardens. Chickens are a great way to help control the pests and the chickens really seem to like the hornworms. However there is still a need to check my gardens everyday to make sure there are no pests. But i don't mind. Looking forward too another great gardening season.

    dishwashing liquid IS A

    dishwashing liquid IS A chemical...hello....

    Everything is a chemical or

    Everything is a chemical or chemical mixture...HELLO

    Thanks for your comment. So

    Thanks for your comment. So true.

    The cocoons were stuck tight,

    The cocoons were stuck tight, and the worm kept flailing sbout, so we quit. It the escaped, time to find a new one!

    Connor, Thanks for sharing.

    The Editors's picture

    Connor, Thanks for sharing. That worm is what they call the "walking dead" due to those cocoons.

    My kids also want it as a

    My kids also want it as a 'pet', so is there a way to take the eggs off? Thanks!

    This is a first! Once the

    The Editors's picture

    This is a first! Once the wasp eggs hatch, the hornworm will be eaten. It is the cycle of life. We have never removed the cocoons and probably would not, but let us know what happens!

    We found a hornworm with 5

    We found a hornworm with 5 white, bumpy specks on it. Are those eggs from a wasp?
    We're guessing they are.

    Those are the white cocoons

    The Editors's picture

    Those are the white cocoons of the wasp.

    We live in southern Arizona;

    We live in southern Arizona; our backyard consists of grass, 4 trees (orange, desert willow, mesquite), and a large variety of roses, lantana, and vines. We have found tomato hornworms wandering in our yard approximately every 6-8 weeks for the last few years. However, for the last couple months we have been finding them dead all over the yard. There have not been any signs of involvement by wasps that we can tell. Their coloring is no longer bright but instead is kind of brown, and they are kind of soft and mushy (it is evident when I pick them up with a pooper scooper--the one I picked up this morning actually tore into two pieces). Does anyone have any idea of what kills tomato hornworms other than wasps? The only thing I can think of that has been unusual around here is a phenomenal weather situation July 15 (2013) when our neighborhood was hit, ripping 2-story high, decades old trees out of the ground, root and all, throwing them into homes, ours included, so I have wondered about the possibility of some soil disturbance or something, I don't know. Help! Thank you kindly.

    We're stumped. We can only

    The Editors's picture

    We're stumped. We can only imagine wasp predation.

    I too live in Arizona. I hear

    I too live in Arizona. I hear from a lot of people that soap and water and then just spray your plants repels the pests away and is safe for the plants. I have yet to try it but after finding 3 of those hornworms today on my tomato plants it will be tried effective immediately. also with some netting/shade screening as well.

    I planted about 6 or 7 plants

    I planted about 6 or 7 plants this yr . We had a ton of tomatoes , some plants were 3 to 4 feet wide, alas I too believe I have these ugly worms. I have found holes right through the tomatoes at times. I have a question , is it safe to cut up the tomatoe and eat what the worm has not eaten ? Are there effective moth traps out there ? I have read about the sticky traps for indoor cereal moths .
    Should my ground be rotatiled in the late fall to get rid of any edges , or worms? Next yr I will start going out to examine the plants in evening I guess , if they make good fish bait , worms beware!!

    I don't know, maybe they are

    I don't know, maybe they are fruit worms , I guess I will have to find one to identify it. Does newspaper work with deterring fruit worms?

    If your pests are tomato

    The Editors's picture

    If your pests are tomato fruitworms, you can control them by picking off any leaves that have tiny white or creamy eggs on them (check both sides of the leaves). Introduce beneficial insects, such as Trichogramma wasps or lacewings. Place row covers over the plants, at least until the plants flower, to prevent adult moths from laying eggs on the plants. Spray Bacillus thuringiensis (BT). Till the soil before and after the growing season. Plant tomatoes away from corn, which is a major host for these pests (in which case, it is called a corn earworm).

    As for whether to cut out the bad part of the tomato and use the rest, we wouldn't recommend it with fruitworms. Because these larvae live inside the fruit, they eat, tunnel, and leave waste inside.

    Hornworms, however, mainly attack the foliage but may also take bites out of the fruit. They do not live inside the fruit throughout their larval stage, however. If your pest is a hornworm, it might be possible to cut out the bitten area of the tomato fruit and use the rest (after a thorough washing); be sure to inspect the fruit thoroughly first, to see how far it has been eaten, and whether the insect has left frass (waste) as well--in which case, we'd suggest not using the fruit.

    I am a preschool teacher.

    I am a preschool teacher. Yesterday, my kids and I found a big fat beautiful Horned Tomato Worm on our tomato plants in our outdoor classroom. He is now living happily in our classroom munching on an endless supply of tomato leaves with 12 very excited and eager kids watching him. We have added tall sticks for him to climb and lots of leaves in hopes that he will build a cocoon and hatch into a moth. They have found books about caterpillars, looked at pictures on the internet, and even collected leaves to feed him. They are so excited to show him to everyone willing to look.

    Yes, I know these worms are pests for most of you, but for this class, this worm is a wonderful opportunity for the kids to experience the bear witness to the magnificent and wondrous cycle of life while fostering language, science, math (rulers to measure him and counting days if he forms a cocoon), cooperative learning, ownership /responsibility, peer interactions, and so much more. For me, finding this garden pest was just an excuse to turn a little pest into a teachable experience.

    Thanks for sharing,Denisestl.

    The Editors's picture

    Thanks for sharing,Denisestl. We can imagine that hornworm munching away as hornworms do. What a great purpose for these otherwise "cute" green caterpillars.

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