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

    Leave a Comment

    My big geraniums were striped

    My big geraniums were striped in just a few days. I didn't think geraniums had many enemies but when I looked closer they are covered with baby horn worms. I want to just cut them way back to try and control the infestation.

    I, too, am a fan of

    I, too, am a fan of hornworms. They have been on my tomato plants and seem to only prune the tops. Almost always, they get the cocoons on them, meaning they are dying. I don't like the idea of something being eaten from the inside out. I just found one on a flower and it has eaten the top out, but I don't care as I get the opportunity to study him up close. Tonight I am observing him trying to find something to eat as there are no tomato plants where he is, and he is trying to eat, I believe, my small yaupon shrub. I don't how he can eat these tougher leaves. I did notice that his mouth is protruding when looking for food. I have never noticed this because I have never seen one at night. Very interesting.....He does not have the parasite cocoons on his back. Hopefully, he doesn't get them. He is pretty large. (I am a former teacher, retired) and a lover of science.

    What a wonderful teacher you

    What a wonderful teacher you are!!

    Good job! Your kids are so

    Good job! Your kids are so lucky to have you as a teacher. The worms may be Pests perhaps, but just the sort of thing to fire a child's imagination and, who knows? May start someone on the road to being a scientist ... Or better yet, an inspiring teacher!

    The first tomato horn worm my

    The first tomato horn worm my dad found in the garden became my pet at the age of 4. They are beautiful, soft and easy to care for. The cocoon and transformation was so fun as a kid, and they are so unusual, I couldnt wait to find a new one the next season. I spent hours patiently tracking their munching and pooping so I could bring it into my kindergarten class to share. We ended up keeping it as the class pet, and watched the transformation throughout the fall. Every year, my old kindergarden teacher would call me out of class to ask if I could find her another worm for her current kids. I brought her a worm each year until high school. I am almost 30 and just started a tomato garden in my first home. I hope I find a fat, green horned worm:) sooner than later...

    Lucky kids in your classroom!

    Lucky kids in your classroom!

    They are very lucky kids in

    They are very lucky kids in your classroom. I have hornworms on my tomatoes but I think you are doing a great job teaching these kids!!!!

    I have done this with my

    I have done this with my kids. When it is time, the caterpillar needs to dig into dirt to form its cocoon. I was surprised to hatch 16 large flies instead of the moth! Fortunately, they were in an aquarium!!!

    Growing tomatoes in a

    Growing tomatoes in a container" the plant box" first time in sev. Seasons for us. In louisiana using 'heat-resistant' tom. Var.good flavor!!! Thanks for great info on hornworm...we thought damage was being done by these little orange guys w/ black legs ~ 20 that hide in a group on cool side of one tomato, on the far side of container fr my two spectacular horn worms on other end.,will use light trick tonight to find more of these green rascals. Now to find out about the orange bugs...thanks FarmersAlmanac. My husband and i are from different generations of gardening., ya'll have restored peace in our garden and marriage.

    I have a hanging Topsy Turvy

    I have a hanging Topsy Turvy and found three of these monsters have eaten everything. I was trying to figure out how they got there but apparently they hatched on my plant.

    The little black bugs with

    The little black bugs with orange bodies and black legs that hang out in groups of 20 or so on the underside of the leaves are milkweed assassin bugs. They're kinda awesome. You're seeing them before they're fully grown. As adults they will assassinate garden pests and suck all the body fluids of their prey. Unless they're just milkweed bugs. If they remind you more of ants, like little soldiers, they're assassin bugs and safe to keep around.

    I'm battling the horned worm

    I'm battling the horned worm as well but this morning found them on my milkweed plant! I've been waiting and waiting for the monarchs to lay eggs but instead an infestation of horned worms! I'll go out and get rid of them now that I've seen a pic of the monarch worms and know that's not what's on my plant! Gardening is such work and I'd like to eat my egg plants growing and not feed the worms!

    What can you tell me about

    What can you tell me about these guys all over my lawn in Albuquerque for the past week? They are about 3" long and eating the grass and/ or spurge on my lawn. They are yellow with red and black spots with a stripe down both sides. Wish I could include photos...

    I draped bird netting over my

    I draped bird netting over my plants to keep the birds off the tomatoes and chilis, and found it has the added advantage of keeping the tomato worms away. The mesh is big enough to let the pollinating insects through, but keeps the large Mandunca moths out.

    Now that gigantic green worms

    Now that gigantic green worms ate all of my lovely tomatoes my grandson found a huge worm in the soil After I had remove the destroyed plant. So my question is. Can I plant some other plant in this same soil and Not have these creatures destroy??

    Tomato hornworms are the

    The Editors's picture

    Tomato hornworms are the scurge of tomato growers. The larvae burrow into the soil to pupate and emerge next spring as a moth. You can plant in the same soil—but not plants of the same famiy. Practicing crop rotation, as well as introducing natural enemies (parasitic braconid wasp, for example) can help to relieve the problem.
    Some folks suggest that growing your tomatoes in containers can minimize the presence of hormworms. Remember, too that crops in containers (or the soil used) also should be rotated for best results.

    Forget the idea that

    Forget the idea that containers are safe zone, I planted 2 patio tomato plants and I have a hornworm invasion.

    I also had a patio tomato

    I also had a patio tomato plant up on a deck and it too has got a hornworm. It is so gross and has devastated the only productive tomato plant that I have. Bad year for tomatoes

    I also container planted

    I also container planted tomatoes in an screened in patio. This morning I removed two hornworms. Not having the heart to kill them, I removed them out to my yard. The more I read, do I really have to kill :(

    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.

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