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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    I found one these critters on

    I found one these critters on my tomato plant about 5 days ago and pinch him off and squshed him on the sidewalk , well i inspect the plant everyday now and not seen one, today i noticed the top of my plant, i only have one, it looked really sparced today, i go look closer and found three huge worms on it, this is also a above ground huge barrel pot i planted it in
    to to keep from these sort problems but it doesnt work, the plant did look like the best one i ever planted in years and now thse worms have devoured some it in just few hours.
    Nothing more agrivating then have something like this destroy something gives u joy, so i hate puting any pestcides on my plants even if it says its safe, what can u trust these days, so i just have to keep close eye everyday make sure i keep them off and kill them.

    I inspect my tomato plant

    I inspect my tomato plant every day and have never had a problem. Today I went out there and every one of my big juicy red tomatoes have been eaten (including all of the flowers). I found 2 green hornworms on my plant; each one is about 5 inches long. I pulled them off, but I'm afraid my plant is a complete waste now. These are some ugly suckers, and I cannot believe how quick they eat. Within a matter of 5 hours, they managed to eat every tomato I had on my plant...Unbelievable!

    HELP! I have a bunch of small

    HELP! I have a bunch of small greenish eggs in bunches and rows all over my patio tomato plants. But its on the stems of the tomatoes not the leaves! What r they? And is there a homemade solution to spray on the tomato stems to kill them? Its been over a week and they havent hatched or anything and i see no damage or insecets on my plants.... Idk what they are but i want them gone... Please help thanks!

    These good be lacewing eggs.

    The Editors's picture

    These good be lacewing eggs.  Lacewings are beneficial insects and eat pests! They love apids. Do not kill them. Perhaps you want to take a sample to your local garden center or cooperative extension.

    I, too, have found these

    I, too, have found these nasty looking hornworms on my tomato plants. I noticed the top stems and leaves looking like they were cut off. After a little inspection I found one hanging upside down on a branch. I fed him to the robins in my yard. I looked around a bit longer and found a tomato damaged on one side. Not far from the tomato, I found another worm. I pulled him off and fed him to the robins too. They were waiting for another tasty morsel. I'm going to get some sevin tomorrow.

    Sevin does not work, Sprayed

    Sevin does not work, Sprayed and powdered, next day I find 2 more so I isolated them, sprayed them with sevin directly. They looked to be irratated but a day later they were alive and well pacing around the edge of the cage trying to escape.

    So what did you use to get

    So what did you use to get rid of the worms? I have rot spots on the bottom of my tomatoes. Does this have anything to do with the hornworms or is it some other problem? Thank you, Susan

    A couple of things: Look for

    A couple of things:
    Look for them at night using a UV flashlight. The worms are a brilliant green while the leaves are purple. Much easier to see. Also the worm feces is a very bright green. So if you see green spots on the leaves, go worm hunting. Don't use UV googles but DON'T LOOK AT THE LIGHT DIRECTLY!
    A very dilute solution of caffeine seems to deter them. Be carful applying to frequently as it can harm the plants. I'm going to try the BT method next.

    What is the BT method?

    What is the BT method?

    I have inspected my tomato

    I have inspected my tomato plants almost dally looking for these horrible pests. Today was the first time I discovered them. They were at the top of the plant. One very large, about 2 inches long and the other one much smaller. I pulled them off and sprinkled the entire plant with Sevin powder. Do these warms grow large so large in a very short time. With my almost daily inspection, I am amazed at the size of them.

    I will tell you that

    I will tell you that marigolds do not work to protect your tomato plants from Hornworms I had 2 plants surrounded by 6 flowering marigolds and the tomato plants were stripped by 3 hornworms in a day.

    Tomato horn worms eat

    Tomato horn worms eat marigolds to. They ate my marigolds then my beautiful pepper plant. I found him, he was huge.

    I found 5 red hornworms in my

    I found 5 red hornworms in my garden. I been planting tomatoes for the last 3 years and is the first time I found this suckers. So, tomorrow will be hunting day. Be aware because I will get those eggs. Thank you everyone for the tips.

    I too have these terrible

    I too have these terrible worms!! They have eaten the tops of 3 large plants, I have picked them off and killed them as I see them. I think I will be going the route of using the BT insecticide treatment. I just couldn't believe how much of the plant these suckers ate before I found it! Unbelievable!

    I recently had two of these

    I recently had two of these on my tomato plant. What helps is put a stick up to them, then they will crawl up the stick. with them still hanging on to the stick walk to the closest ant bed and throw the stick with the worm still on into the ant bed. Then watch the FRENZY!

    I read in a book about garden

    I read in a book about garden pests that you can spray tomato plants with a mixture of tabasco sauce and water to get rid of tomato hornworms. It did not give the ratio of tabasco sauce to water. Has anyone tried this? Did it work? How much tabasco sauce did you use in a quart of water?

    Yes I tried it. It's one

    Yes I tried it. It's one ounce of tabasco per gallon of water. I used it several weeks ago....found 2 big horn worms today. You try and let me know if it works.
    Thanks

    I've heard that too.

    I've heard that too. However, these catapillars devoured half my jalepeno crop...ate the peppers right up to the stem. So am am doubtful that tobasco would deter them?

    You have to add dish soap or

    You have to add dish soap or vegetable to the mix. They hate both.

    Used Dawn dish soap diluted

    Used Dawn dish soap diluted in sprayer, also Hot Chili Sauce, garlic mix it didn't faze them! Can't use Neem Oil due to the heat. Going to try BT.
    Thanks

    I read a few articles last

    I read a few articles last year regarding the use of hot peppers, garlic and water, that you spray on plants to keep such as aphids, hornworms, etc, away. I can tell you that it was not only messy, but it didn't work. I tried everything except for bt, which I've read about this year. I tried sevin dust but for some reason it made the leaves of my tomatoes turn very hard . I had 7 tomato plants last year and the few tomatoes that I had were very small and not good.
    I had 2 square foot gardens, that I grew okra, eggplant, beets, peas, zucchini, jalapeños, Lima beans, radish, green beans, bell pepper, and cow peas, which all yielded a great crop. I also grew pickling cucumbers on the east side of my house that also did extremely well. I did have a problem with aphids, and read that neem oil worked well, but for me after it got hot, it killed a few of my plants. I live in the Southern Central Valley of California, and the summer temperature easily tops 100+ degrees sometimes a month or more straight. It was 112 degrees just two days ago. So I've got to be careful what I use on my plants.
    I planted pickling cucumbers again in the same spot as last year. I noticed that the leaves were being eaten rather quickly, so I researched the Web, most site's either said that it was slugs or a beetle. I put down slug bait, and the next morning, I noticed that more leaves were eaten. I went through the plants, turning the leaves over to find a slew of hornworms noshing away on my cucumbers.
    I haven't found anything yet that's worked without harming the plants, other than inspecting and picking off the hornworms by hand. I will be definitely looking into BT as a remedy. It is a cornstarch based bacteria, once the hornworms eat it, it will paralyze the stomach and they die. Its also approved for organic gardening. I hope that this helps you.
    Good luck with your garden.

    I haven't found any big green

    I haven't found any big green worms. Just little fuzzy ones eating holes in the tomato leaves. The leaves look like swiss cheese. Are these the baby horn worms? Is there any way to get ride of them before they turn into the big worms and destroy the fruit and the plant? They are all tiny and fuzzy and black and white, about 1/4 inch at most right now.

    Another of nature's

    The Editors's picture

    Another of nature's mysteries: It sounds like you have tomato fruitworm, which will soon become a moth...but we can't be sure.
    Yes, they could destroy the plant, esp the fruit. If it's the fruitworm, some sources recommend Trichogramma spp. egg parasites; the larval parasite Hyposoter exiguae; and predators such as bigeyed bug and minute pirate bug. (The idea is, fight nature with nature.) However, some even advise using organically acceptable Bt (consult your local extension or nursery). In the meantime, pick them off and eliminate them.

    a friend told me she heard

    a friend told me she heard that putting pennies around the base of your plants will stop the worms from crawling up the stalks, something about the copper in the penny they dont like, will this not harm my plants?

    Many gardeners say copper

    The Editors's picture

    Many gardeners say copper pennies deter snails and slugs. However, only pennies before 1982 are made of copper; now they are mainly zinc. See our Pest section for good ways to deter differently kinds of worms.

    Since the moth lays the eggs

    Since the moth lays the eggs on the leaves, it makes since to me, that the worms hatch in the leaves, and never have to crawl up the stem, that is in the ground. Thus the penny, whether it has copper in it or not, would be ineffective.

    I don't think that idea will

    I don't think that idea will work. Pennies haven't been made with copper for many years.

    That makes CENTS!

    That makes CENTS!

    Has anyone tried to use

    Has anyone tried to use beneficial nematodes to control tomato hornworms? We had a flea problem in the backyard and were looking for nonchemical flea control when we came across beneficial nematodes. We released three different varieties which will invade and use pests in the soil as hosts, killing them. beneficial nematodes do not harm plants or animals, only soil dwelling pests.

    I used to have hornworms I

    I used to have hornworms
    I used to get hornworms on my tomato plants every year but ten years ago they disappeared, and this year I discovered their demise was caused by Spined Soldier Bugs that live in my garden. The Soldier Bugs look like brown watermelon seeds with a tent-shaped back and sharp points on their shoulders. They pierce other bugs with a sharp beak and suck their juices out, but their favorite food is tomato worms and every plant has one patrolling it.

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