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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    This year I put ducks in the

    This year I put ducks in the garden and they patrolled for bugs all season long. I found not a single hornworm on my tomatoes!

    I remember this from my

    I remember this from my childhood and it works. But only if ducks are allowed where you live which unfortunately is not the norm these days.

    I seem to get these SOBs

    I seem to get these SOBs every year. Have done everything from seven to plucking them off. I HAVE discovered that if they have stripped a branch of leaves and you pluck off the worm that the leaves WILL grow back and they CAN produce after that. Now that I know what the Moth that starts this crap looks like I can KILL the MOMS and DADS of these dang things. Side story. I have two container pots of tomates that I have brought in for the season, and I am getting tomatoes from them. Imagine my surprise when I found TWO of these SOBs on my INDOOR TOMATOS! That SAME day I found a HUGE moth in the kitchen, across from where the plants are. We took it outside. If I had known then that THIS was the MOTHER!!! I would have killed it and been done with it. Noooo I let it LIVE! "I'll get you next time you ugly!"

    HA HA HA Diann! Your comment

    HA HA HA Diann! Your comment made me laugh! :] I just looked up their adult form photo so I can kill them BEFORE they destroy my tomatoes!

    Loved reading this. I found

    Loved reading this. I found an UGLY on my tomatoes yesterday and tried to figure out what the heck it was. Thanks to this link, I identified it and am now looking for the MOTHER of this SOB! Mine had eggs attached, which I am assuming are wasp eggs. It is now in a zip lock bag and not long for this world. Perhaps I should let it go because the baby wasp will soon have it to snack on...or I'm assuming so! Thanks for your enlightening comments! Happy Gardening!! Fondly,
    Sonji

    Thanks for the laugh! I just

    Thanks for the laugh! I just came inside to get on the internet to identify this little creature because they have destroyed 4 tomato plants overnight. I squished two that I found but I know there are more out there. I couldn't wait for the white pods to change into a wasp!!! There has to be a solution to this problem. Somebody needs to HELP us out here so we can enjoy our fresh tomatoes.

    so if i understand this

    so if i understand this correctly,if i have found 2 hornworms,chances are i will find many more?? i have never had this problem before in my garden,could they have been in the siol of the plant when i purchased them?

    Hi, Nancy, Thank you for your

    Hi, Nancy,
    Thank you for your interest in The Old Farmer's Almanac.
    To answer your first question, yes, it's certainly possible that you will find more hornworms in your garden. Watch to see if the leaves on your tomatoes "disappear" (get eaten) and for black "droppings" (poop). You might even find that bites have been made in your tomatoes.
    As to whether they came in the soil, we can only offer a maybe. Just because you never had them before doesn't mean you'll never have them. Eggs are deposited on plant leaves and the mature larvae drop off into the soil at maturity. They dig into the soil where they form a pupal cell before attacking the plant.
    Sources suggest that tillage can eliminate as much as 90% of the larvae. So can crop rotation.
    One thing to note: if you see a hornworm with a lot of little "white things" on it that resemble grains of rice, let it live! The white things are parasites that will kill the worm and grow/emerge to become predator wasps.
    I hope this helps!

    I'm a novice gardener with a

    I'm a novice gardener with a few herbs and tomatoes in my front yard.

    I'm surprised to hear about these plants that are supposed to keep the hornworms away. I have a very small garden and it contains one cherry tomato plant, along with two basils and two rosemarys, among others.

    I first noticed that some of my lower and inner leaves were wilting and dying, but I thought it was because I have to rearrange the plant pretty often to support it. It wasn't until today that I saw some stripped branches and huge hornworms. Now that I look at it, it seems like almost all of the inner leaves and up to a third of the outer leaves have egg pouches on them! What can I do? I don't want to kill bees, as they're the ones making my tomatoes possible. Is the pesticide the right choice for me?

    Most of the worms I found were parasitized, but it seems like there are too many for them all to get that.

    Thanks for your help!
    ~CarolAnn

    Hornworms usually start at

    The Editors's picture

    Hornworms usually start at the top of the plant, eating interior leaves. Handpicking is probably best, since you have a small garden. Use gloves to grasp them and drop them into a bucket of soapy water or, if you can stand to, squish them. Gently scrape the eggs off the leaves and destroy them. If you can, it’s good to leave the parasitized hornworms alone so that the braconid wasps can hatch from the eggs; the caterpillars will die at that time. If this doesn’t work, BTK (Bacillus thuringiensis subsp. kurstaki) can be sprayed on smaller caterpillars; it will not affect bees.

    Thank you for the

    Thank you for the info!
    ~CarolAnn

    We had 4 of these worms on

    We had 4 of these worms on our plants this year and I had never seen the wasp eggs on them in the past so I assumed they were their own offspring. They were completely covered with them. If I had known what they were, I wouldn't have thrown them in the firepit. Worked good to kill them! Next time I will just let nature take it's coarse and let the wasps hatch.

    I have been gardening and

    I have been gardening and growing tomatoes for years. This is the first time I have seen one of these owful worms and by the time I found it it had destroyed my tomatoes and eaten nearly all the leaves on two plants. This thing was as big around as my thum and about 4 inches long. I pulled both plants out and tossed the whole thing since I didn't know what it was or if there were others lurking around. I have never ever seen one of these on my plants before. Now I will be buying tomatoes until next summer.

    I have tried every method the

    I have tried every method the reader above have suggested for the last 10 yrs. None of them work except for 7 dust, and pluckin em off and giving them to the chickens. (they appreciate the ugly sobs)

    If soapy water will take care

    If soapy water will take care of the worms when placed in it will it take care of them if I spray soapy water directly to the plant? Thanks

    Yes, but don't overdo it. A

    The Editors's picture

    Yes, but don't overdo it. A few drops in a LOT of water. Specifically: Mix 1 teaspoon of clear liquid dish soap in 1 quart of water to make an insecticidal soap. Spray just when you need it--and spray in early morning or late evening-or it will burn your plants.

    Last year I had eight large

    Last year I had eight large hornworms on two small container tomato plants. This year I am going to try diatomaceous earth. I have read that it destroys the insides of the worms. It has to be dry to be effective, dust it on the plant and soil. It is organic and harmless to pets and humans.

    I prefer Seven and old

    I prefer Seven and old fashioned hand pluckn to remove those sob's. So best of luck in your garden.

    I decided to plant dill

    I decided to plant dill between my tomatoes this year and while the worms are back, they seem to like climbing the dill more and are much easier to spot. I have tried most methods for ridding my garden of them but being diligent and hand picking them works best. Get a good flashlight and go out a few hours after the sun has gone down. Best of luck!

    I have green worms that eat

    I have green worms that eat everything in the garden, veggies and flower leaves. They especially like morning glory leaves. They are not tomato hornworms. There is no horn, what are they and how do I get rid of them?

    We believe that you have an

    The Editors's picture

    We believe that you have an inch worm problem. You can try to spray with horticultural oils or use Bacillus thuringiensis, a wilt pathogen that is only toxic to insects.

    Kill two birds with one

    Kill two birds with one stone.....with each tomato plant you plant, also plant a basil plant about a foot away. You will not see a horn worm all season and you will always have fresh basil....learned this from grandmother over 50 years ago. Been doing it all my life...trust me it works

    Sorry guys, but I have

    Sorry guys, but I have marigolds and basil in the same pot as the worms. That is not working.

    same here had both marigold

    same here had both marigold and basil planted right under and next to my cherry tomato plants and my plants were destroyed.. help please i have gone out to my raised beds last week as i had some radishes planted there last fall and picked some ,and found live hornworms right under the surface of the soil,this is Feb. and the soil is frozen...what do i do before planting comes

    The pupae overwinter in the

    The Editors's picture

    The pupae overwinter in the soil. Put black plastic on the soil where you are going to plant your tomatoes. This can help prevent the moth from emerging in spring and laying eggs on your plants. The eggs will become the horn worms.

    I live in Maine so if I

    I live in Maine so if I tilled the area I was going to plant in and placed the black plastic over it until it was safe to plant, this would possibly kill the moths? I think sometime in April is possibly when I could till but planting doesn't happen until end of May. Thank you!

    Considering that I do not

    Considering that I do not have tomatoes in my yard; I'm growing three different varieties of basil and hoping to sell them in my local farmers' market, and the hornworms are decimating my basil bushes, I think we can re-evaluate this particular notion of companion planting. I had aphids in my basil, whiteflies too....got rid of them with daily spray of organic soap and weekly neem oil treatment. Both of these I do as early in the morning as possible so the plants don't "cook". The hornworms are a most unwelcome surprise that I'm going to deal with by handpicking.
    I'm going to try woodash on a section and see if that helps. Fingers crossed

    PS. Not trying to discredit you, but I suspect there is something in addition to your basil (maybe wasps or assassin bugs) that's keeping the bugs off your tomatoes. Wish all were as lucky as you and that your luck never wavers.

    This year has been terrible.

    This year has been terrible. I usually plant marigolds but didn't this year..We have taken over 70 hornworns off. I'm sure there are more. They are destroying my 4 tomatoe plants...I have two basil plants next to one of it and that hasn't detterred them at all. I'm wondering is it too late to plant the marigolds this year? The tomatoes are still green what is left. They are heirlooms and I live at 3800 ft. Thanks for any anwers you may have!

    I haven't gardened in years.

    I haven't gardened in years. This year was the first time we purchased three tomato plants from a co-op. When my Early Girl hit 4 ft I noticed leaves missing and there a huge 3" ugly hornworm on the stem (blending in). Since we've never had a garden in the area we planted the tomatoes we were wondering if eggs were in the co-op soil... anyone else had this problem?

    I took the article in OFA to

    I took the article in OFA to heart and planted marigold plants amongst my tomatos this year and we had NO tomato worms at all. I'm assuming it worked, we have ALWAYS had these grose worms and they can devour a plant in short order.

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