Tomato Hornworms

How to Identify and Get Rid of Tomato Hornworms

Tomato Hornworm
Amanda Hill

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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.

    Reader Comments

    Leave a Comment

    I'm sure this is an old post

    I'm sure this is an old post but I'm a first time grower and have spent the day investigating tomato & tobacco hornworms because after returning home from a couple days away I checked my plants this morning and was shocked to find the entire top deleafed and only 2.5 clusters of grape tomatoes remaining.

    I'm adding this reply because my plant is in a container AND I did plant marigolds at the base of it. I have pulled 10 of these critters off my plant.

    So containers are not immune!

    I only want to know now if the remaining plant can be saved?

    We were blown away today when

    We were blown away today when we discovered a 6 inch lone horn worm demolishing our Sunflowers from the ground up. He in jar now awaiting his demise. Lord I hope I never see one of them again. Took pictures.............UGH!!

    Today I noticed that I had 3

    Today I noticed that I had 3 worms on my plant but they had white eggs on them which are baby wasp that eat them so ill let the wasp do the work.

    I have a flower bed full of

    I have a flower bed full of moon flower plants, and these hornworms LOVE them! I have picked off about 20 in the last two days. So I've been searching how to get rid of them. I came across some recipes for making your own pesticides out of all natural ingredients. Here is one...
    Onion and Garlic Spray
    Mince one organic clove of garlic and one medium sized organic onion. Add to a quart of water. Wait one hour and then add one teaspoon of cayenne pepper and one tablespoon of liquid soap to the mix. This organic spray will hold its potency for one week if stored in the refrigerator.
    I have not tried it yet, but plan on it!!! They eat my plants just as you describe them eating tomatoes!!!

    I used ducttape around my

    I used ducttape around my huge barrel I
    have the toamtoe plant int, so far i havent seen one, it took 6 worms and half a plant now damaged befor i figured a way keep the darn things away.
    Only bad part is i have to replace the duct tape every 3 days, depends on the weather cause the sticky part wears off quick being out in the high humidity and then sun beating down on it all day.

    I am so glad I saw this page.

    I am so glad I saw this page. First I was gonna let the caterpillars be, hoping they'd turn into cute little butterflies! After reading the problems they cause, I decided to get to work. They had already eaten huge portions of my plant to the stem. I found about eight worms covered with the wasp pupae, all small and still (presumably dead), so I let them be. I removed three huge ones that were uninfected and still active. Will the friendly wasps take care of the rest? I hope so!

    Has anyone tried neem oil?

    Has anyone tried neem oil? I've heard it works very well and is about as safe as anything can be.

    I found a huge horn worm on

    I found a huge horn worm on my tomatoes and bean rollers on my beans. I used neem oil and all were gone. They say to use for 7-14 days to make sure. I am using every other day for 7 days. But, I haven't seen any more worms.I use at early evening so it can work all night. Neem oil can't take full sun from the day!

    Neem oil can't be used on

    Neem oil can't be used on plants in hot climates. I tried it last year and it killed the pests as well as my plants.
    I live in the Southern Central Valley of California, where the temperature is very hot and dry. We have temps of 100+ for at times a month straight and sometimes even longer.
    I believe that Neem oil cannot be used in temps over 85 degrees. I've read about a cornstarch based bacteria called BT, that is effective at killing hornworms, and its not harmful to plants or animals.
    Good luck with your garden.

    Oh my goodness!! I just found

    Oh my goodness!! I just found three large hornworms on my tomato plants and pepper plants. I kept inspecting my plants and I found eggs in a leaf. Took those off too. Then I found a baby hornworm. Im so upset! This is the first time we have done a vegtable garden. Im pretty proud of my work. I will not let these pesty little green things ruin it.

    I've been finding adult

    I've been finding adult worms, teeny worms and larvae on backsides of leaves every single day on my plants. I've been picking off no less than 5 a day. Some days 10-15. The natural gardening site recommends 1 cup of vegetable oil, 1.5 cups water and 2 teaspoons dish soap in a spray bottle. You can add white pepper or cayenne if you lie. If you have really hot days, you should spray the concoction on at dusk and make sure to shower the plants with water before the heat of the day to avoid leaf burn. Then repeat the process. it requires some discipline but, they tell me it works and they should be long gone. I'm starting tonight.

    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.

    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.

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