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

    safe greens

    The Editors's picture

    It should be OK; we haven’t heard about any cautions regarding hornworms affecting edibility of crops in that respect. After harvesting, cut out any damaged areas and throw out any rotten leaves. Then wash the greens thoroughly just before eating, using cool running tap water. You can blot the leaves dry with a paper towel or use a salad spinner. Be sure that your hands and any utensils/tools and food preparation surfaces are clean. (It is recommended that hands are washed for at least 20 seconds with soap and warm water before handling food.)

    worms on tomato plant

    i have what i thought was the cabbagelooper doing damage to my plants but now i'm not so sure. i've been collecting the cocoons at various stages and have come across many that look like a worm encasing hundreds of eggs. could this be a way of reproduction for them that i'm unaware of?
    please advise

    eggs

    The Editors's picture

    Are these cocoons on a caterpillar? See the photo of the tomato hornworm with the braconid wasp cocoons above - these are one insect per cocoon. Braconid wasps are parasites of the hornworm. If you see these on a worm, leave them be. The hatching wasp larvae will take care of the hornworm pest.

    The eggs of a cabbage looper are laid with no protective covering on leaves, singly or in small clusters, and are whitish yellow to green. Each pupa is encased in a thin white cocoon under foliage; the pupa itself is green, then turns brown to black, before transforming to a moth. A few insects make egg cases, such as praying mantids and spiders (egg sacs), which contain many eggs. A common tomato pest that might do this, though, does not come to mind at the moment.

    Fruit Trees - plums ,Figs , Tangerines , n more

    Don't like worms to see in my garden . Thanks for all the Infos.

    Hornworms

    I have this worm eating my tomato plants,but it is black with gold v-stripes. What should I do with it

    tomato plant pests

    The Editors's picture

    This sounds more like an armyworm. Besides handpicking, you could try applying the natural bacterium Bacillus thuringiensis (Bt) for control. Talk to your local garden store.

    Tomato Hornworms

    We're under attack!!! Never one to be afraid or grossed out by bugs, but these are no bugs! They're creatures! We never had them before & planted our tomatos & peppers in containers with new soil. We're checking daily & removing them regularly. Also spraying with soapy water. Lots of great info on your site & now that we know about the wasp eggs & the villain moth, we'll be on the hunt. Thanks!

    Saw one hornworm

    I found and removed one large hornworm from my tomato plants today. This is the first time I have ever seen one. Can they be found in isolation, or do I probably have more?

    Tomato Hornworms

    The Editors's picture

    If you find one tomato hornworm, look for others.  Their mothers deposited a bunch of eggs from which they hatch. Plants should be examined at least twice per week during the summer to check for tomato hornworms. They’re easy to find because they’re big!

    hornworm

    While pulling outthe last of the tomato plants I found 2 hornworms, one about and inch long and the other about two inches long. The smaller was covered with the wasp eggs but the larger was not. I have a 5 year old nephew, I gave him the worms and he put them in the little screen cage that he has. The next morning the larger worm also has these eggs. Does this mean that the worm was 'attacked' by the wasp at an earlier time. how is this process done, does the wasp 'bite' once or does one 'bite' produce all of these eggs?

    hornworms as pets

    The Editors's picture

    Hi, Mary Anne, Yes, it is possible that the worm was attacked by the tiny wasps before it went into the cage. The “eggs” are actually cocoons; the eggs were laid under the “skin” of the hornworm and these are the result. As for how it’s done…a special type of braconid wasp inserts its eggs into the caterpillar (hornworm). The eggs hatch into wasp larvae that feed on tissue in the caterpillar. This eventually changes the color of the hornworm but—fear not—it is still alive. The wasp larvae eventually chew through the hornworm’s skin to pupate…and each white “egg” attached to the caterpillar/hornworm is the cocoon of another special braconid wasp. Before long, the new wasps will break free and be ready to mate and attack next year’s hornworms.

    There is a lesson—or one heck of a bedtime story—here for you and your nephew. Good for you for going after the detail! And thanks for asking us. (We learned something too.)

    Tomat worms

    I found 4worms destroyed them. About thirty minutes later found another. Today I have checked my plants 4 times and just found one that was not there earlier. I have marigolds close to them. Never had this many worms on my plants before. Does the marigolds draw them?

    Hornworm

    You need to add jalapeño to the food list

    Tomato hornworms

    I only planted two tomato bushes and two green pepper bushes this year. This morning I came across these buggers. I thought my bushes were looking a little wilted after I picked a big bowl of tomatoes last week. I picked off 7 and am so creeped out about these bugs that I may just cut down the bushes!! I have never had these bugs in the 25 years I have been planting. They are not on my green peppers but there is a lot of dropping on the leaves so may pull them out too!

    Tobacco Horned Worm

    This was a great article. :) You do need one correction though. You say these worms do no sting. You have never got tapped with that horn on the back then. lol They do sting and it feels like fire when you get hit. Adults need to be very aware when removing them not to get stung and children do not need to handle them because they can get hurt.

    ... it does not have the capability to sting or pierce the skin

    If you have ever suspected that you have been bitten by a tomato or tobacco hornworm, chances are it wasn’t a hornworm that bit you. A tomato or tobacco hornworm (or any hornworm or insect for that matter) will do whatever it can to protect itself, especially if you handle it for too long. However, it doesn’t defend itself by biting. A hornworm will spit out the contents of its stomach, it will wiggle and thrash about, and it may even wrap itself around your finger, but it does not have the capability to sting or pierce the skin.

    (Ref: www. allaboutworms. com/tomato-and-tobacco-hornworms)

    Thank you

    Thank you

    Hornworm tragedy

    I agree with the one comment as to “Feels like fire” , in reference to being stung/bitten by these things. Anyone that has felt the sting/bite from one of these things will never pick one up with their bare hands again. The first time I had this happen I thought possibly it was me or a wasp encounter etc.

    The second time my father-n-law tried to warn me to look for them before picking the tomatoes. Too late as one was under a leaf above the tomato and it pierced the back of my hand. Felt like fire and a stabbing pain all in one. I do not claim to understand whether a bite or sting, but. I now look before I pick tomatoes and I use pliers to remove these things. As they may have gotten me twice, but never a third time if I can help it.

    wasp larva

    So the white grains on the back are wasp eggs. How do you insure they multiply?

    Hornworms and wasps

    The Editors's picture

    Hi Joe, If you see a hornworm with eggs on its back, just leave it there!  It will indeed multiply, carrying destroyers of hornworm brothers, sisters and descendants. I believe these wasps are commercially available, but it’s an expensive way to go. The best you can do is provide a nice habitat. They love flowers from the Apiaceae or Umbelliferae family such as angelica, carrot, celery,coriander (cilantro), dill, fennel, lovage, cow parsley, parsley, parsnip, cow parsnip, sea holly, and more. Allow some herbs to flower.

    Godzilla on my grape tomato plants

    I was horrified today to see this big fat green creature on my tomato plant stem gorging itself on my grape tomatoes. Not wanting to touch it, I managed to get it off the plant but not without a struggle and smashed it against the wooden garden container. Thankfully I found your website and tomorrow will see if any more are "out" there and look for their eggs. I already have one dead plant but can't say it was due to this creature. With the exception of the grape tomato plant missing growth at the top, my five remaining plants look o.k. I also have eggplant and peppers, all doing nicely but according to your site, hornworms also "fancy" both so I'll be checking those as well. Should the vegetable oil and Murphy's oil be used as a preventative or sprayed directly on the worms???

    Oil on Hornworms

    The Editors's picture

    Hi Toni,

    Go ahead and spray it directly on the hornworms. The oil smothers and suffocates them.

    Hornworms

    I picked off nine (9!!!) this a.m. and I just checked yesterday. I HATE these things; they have already destroyed the tops of three plants. HELP; they are so hard to spot before they get so big that they done a lot of damage. Any suggestions for the already in the ground plant?

    tomato hornworms

    The Editors's picture

    Handpicking is one of the best things that you can do – you might try going out after dusk, when they are more active. It is said that if you shine a blacklight UV flashlight (found online or in hardware/building supply stores) on the leaves, the worms will show up as bright green. Look under the leaves for them. Caution: When using a blacklight, follow manufacturer’s directions; UV light can damage eyes and skin. Use UV blacklight safety glasses.

    In daytime, also check the leaves and remove any green eggs that are laid underneath. See above for biological and chemical controls. Do not remove any hornworms with cocoons on their backs – signs that parasitic braconid wasps are already at work. Encourage beneficials in the garden; plant borage (said to repel hornworms). Till your soil in fall to expose overwintering stages of the hornworm larvae.

    Tomato hornworm on my habanero plants

    I'm in a condo and have 9 pepper plants in 5 gallon buckets on my patio. Yesterday I pulled off and flushed down the toilet a green caterpillar, later identified as a Tomato Hornworm. I'm just gathering information on these as I'd never seen them before yesterday and it's my second year of growing peppers in 5 gallon buckets.

    Hornworm damage

    Is it okay to cut off hornworm damage? It might make it easier to see if I missed any while picking them off.

    Cut Off Hornworm Damage

    The Editors's picture

    It is alright to prune some of the damage, but remember that the more severely you prune the foliage, the more you limit plant growth. The foliage has already experienced damage from the hornworms, so you should be very selective about any further pruning. Trim to the point where you feel you will be able to notice any hornworms appearing, and be sure to remove the hornworms as soon as you see them. 

    cucumbers

    My cukes are growing but the are turning up on the ends they are not and inch long.What could be causing this

    misshapen cukes

    The Editors's picture

    Misshapen cucumbers can be a result of a few things:

    • possible poor pollination which could be due to lack of insect pollinators; bees are cukes’ primary pollinators; to alleviate, eliminate pesticides, if you use them. Consider planting some flowers to attract pollinators.

    • environmental stress, such as nutrient-poor soil, lack of water, or lack of sunlight; to alleviate, saturate the soil to root level when watering, add a liquid fertilizer to the water (1 tablespoon to a gallon of something like a 24-8-16 fertilizer) and apply every seven to ten days. 

    • disease, sometimes those carried by insects; to alleviate, get the cukes off the ground, by laying straw as mulch or trellising the cukes

    Tomato Horn Worms

    Hate those things....and always used to use powder that was toxic.
    This year and so far it has worked. I take equal amounts of salad oil and murphy's oil.
    Put in a water spray bottle shake and go out and keep it on the plants. I do it about 3x a month. Cheyenne pepper in the mixture is a sure fix. They hate the stuff.

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