Worm War I: The battle of the tomatoes

By Debra Eschmeyer

There’s something about caring for a tomato plant that brings out every nurturing instinct in me. I am literally in constant motion during peak season, in a long, choreographed dance of pruning, irrigating, mulching, deworming, and finally, harvesting — my own version of tomato salsa.

But there may be another living being that likes tomatoes more than I. Actually, a lot more. This vagabond in my garden not only dines on the fleshy fruit, but also on the leaves, as he clings camouflaged on the curvy vines! I suppose it’s not really a fair competition, because this is his sole means of fuel until he burrows into the ground to morph into his next phase of life as a moth.

So should I pardon the ephemeral life of the wryly named tomato hornworm?

I think not! He has the audacity to arrive every July, lusting for lush Brandywines, Cherokee Purples, Valencias, and Striped Germans to partake with no invitation in the fruits of my work that I have nourished and invested in since March. No sirree, this colorful green intruder pays me no respect for the feast I have cultivated. His gluttonous ways are consuming the potential of future salsas, sauces, and soups! Known formally as Manduca quinquemaculata, tomato hornworms are the larvae of hawk or sphinx moths. The last larval stage is the most destructive: once the worm reaches 3-4 inches, the worm consumes more than 90% of the total combined foliage, which can be death to a tomato plant.

I’ve become obsessed with finding evidence of the manduca’s mighty appetite: tiny piles of brown or green droppings is a quick sign of their surreptitious presence, followed by the emaciated vine — stripped of leaf and budding blossom. And if you get close enough to the plant and slightly wiggle the leaves, you will hear their warning call. A shrill “schtick, schtick” resonating through the thick jungle of tomato leaves exposes their presence. Then the plump, insatiable worm will appear: the meal, and the masquerade, over.

Plucking their tightly grasped hooks off the vines, I drop them into a bucket of water. Other generals in the tomato wars have taken a more adventurous life-cycle approach: fried green tomato…hornworms. For now, I am going to pass on eating the chlorophyll critter and consider its capture from the camouflage-friendly canopy another tomato saved — and another battle won in the Worm War.

Debra Eschmeyer is the marketing & media manager of the National Farm to School Network and the Center for Food & Justice; she also works a fifth-generation family farm in Ohio, where she raises organic heirloom fruits, vegetables, and chickens.

13 Responsesto “Worm War I: The battle of the tomatoes”

  1. Cholestatrim says:

    My wife and daughter jessie nourishes orange trees and have only four in the backyard. These type of worms arrives in at fresh flush and starts eating everything and leaving only sticks in plants. This time jessie will after me for pesticides which I say NO. Am amedical practioner for humans!!
    I always says them to pick them and kill. They tried and everyday morning she says the count 20,35,56,108…goes like this and plant suffers a lot.
    A guy came yesterday and suggested some biocontrol and they are after him now.
    Added your blog into favorites and let them go thru it …may help.


  2. Kevin S. says:

    Aha! That must be it, in my yearly battle of the Brandywines! Between the squirrels and possibly the hornworms, I’ll be lucky to get anything off the plants this year. Sigh. I hadn’t thought to check for the hornworms, so that is the first thing up for tomorrow in the ‘mater patch. Question: Do hornworms eat cucumber plants too?

    Best of luck with the tomatos!

  3. Debra Eschmeyer says:

    Hi Kevin,
    Sorry to hear about your tomatoes! I know the hornworms eat peppers, eggplant, and potatoes, but I have never heard of them crunching on cucumber.  The best time to check for the worms is early morning and late at night b/c they make their way to the top of the plants at that time. I am off to go do my usual morning check! Good luck,

  4. Kevin S. says:

    Thanks for the tip: I have some pepper plants that have suffered the same damage, so I’ll keep checking. Those hornworms are good at blending in with the leaves!

    Fortunately, I have some other tomatos alongside the Brandywines, so I should be able to get some fresh ones pretty soon. For some reason the Brandywines seem particularly vulnerable. A pity, since they taste so GOOD! I can still remember one I had two summers ago, a one-pounder I ate sitting at the kitchen table, sprinkled with a little salt and olive oil. Mmm, mmm.

    Hope springs eternal, so here’s to a good crop!

  5. Julie Cummins says:

    This is one of the only garden pests that gives me the creeps (OK, that and Jerusalem crickets, but at least those have a cute face). They really cling to the plant and I don’t enjoy ripping them off (though I’m fortunate to have never had too much of a problem). The hornworm looks like something chickens would absolutely love. I bet if you saved the bucket of worms for a friendly chicken, you would have fun watching them get devoured. Poetic justice.

  6. Debra Eschmeyer says:

    I fed some of the hornworms to the chickens, which they loved, but then I read that there may be a toxin in the hornworm that could hurt the chickens.  If anyone has sound evidence that hornworms are fine for chicken consumption, I am all for continuing the food chain.

  7. Matt Regan says:

    Ok, I’m going to go out a little on a limb here.  There’s a bacteria called Bacillus Thuringiensis that paralyses the gut of hornworms (and other worms and larvae), essentially killing them.  It’s organic, it’s non-toxic to plants and other animals; even the powdery delivery mechanism (cornstarch) is benign.  Bacillus Thuringiensis has to be ingested by the worm to take effect, so they can still eat part of a plant.  Home gardeners can buy ”bt” at almost any good garden store; other organic-minded gardeners I’ve spoken to swear by it.  Personally, we’ve had great luck using it (and we use it sparingly).

    You can find more about “bt” here:  http://www.bt.ucsd.edu/organic_farming.html.
    I know this seems somehow seems a little unnatural (since it’s engineered), although nature did give us this bacteria.  Hope this doesn’t offend anyone : )

  8. Matt says:

    This may not be for purists, but there is a natural bacteria called Bacillus Thuringiensis that’s very effective against hornworms (and a lot of other moth larvae species too).  When the worm ingests the bacteria, it paralyzes its intestines, and kills it.
    I know, it sounds suspect…But Bacillus Thuringiensis (or “bt”) was discovered more than 100 years ago, and has been used as an organic, natural pest deterrent for about as long.  It has been studied extensively and has not been found to persist in the soil or waterways, and is harmless to plants and animals.  Many organic gardeners I know swear by it (it is within USDA Organic guidelines), and I’ve used it on my own organic garden with great results.  Most good garden stores carry it — it’s a powder consisting of a small percentage bt spores (the “carrier” is usually cornstarch).
    More information is here:  http://www.bt.ucsd.edu/organic_farming.html.
    Hope this is helpful (and not offensive to anyone!)  : )

  9. Debra Eschmeyer says:

    Thanks, Matt! Great insight and advice. 

  10. asha says:

    I don’t have a garden at the moment (living in the middle of a big city), but when I lived in the south I grew lots of yummy tomatoes. I could often be seen in high summer with a pair of scissors in the tomato patch. A quick snip in the middle is a very swift death, chemical free, and there’s no need to wrestle the tenacious worms off the vines (which always creeped me out). Good luck.

  11. Jan says:

    Just found the top of my potted tomato stripped of leaves and two of the green tomatoes chewed.  Have searched the remaining plant and other pots but cannot find a thing…..Could these things just disappear?

  12. Debra Eschmeyer says:

    Yes, they will disappear as worms and reappear as moths two weeks later! Once the hornworms mature, they bury themselves in the ground to then pupate, and return to the garden as moths, and the process starts over again…mate, lay eggs, etc. That is why it is critical to find them as early and small as possible! Good luck.

  13. Steve says:

    They are a pain in the arse, but my chickens love them!