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by Amber

Bug Battles: What’s Eating My Tomatillos?

The first year I grew tomatillos, I had one plant. The weather was awful. I finally got a couple of handfuls of ripe ones right before the early frost, but not enough for canning salsa. The next year, I planted six of them. I got wheelbarrow loads of tomatillo fruits! The weather wasn’t necessarily better, but cross-pollination makes them exceptionally prolific.

Unfortunately, some tiny larvae made pinhole tunnels in 99% of the harvest. It was a total loss!

Over the winter, I tried to discover what happened to my mother-load of tomatillos. Years have passed, and I still have no clue. The closest resolution I can find is tomato pinworms, but they’re bigger than whatever does this to my crop.

A friend of mine, an inspector at the Dept. of AG Plant and Disease, offered to test a specimen at the lab for me. But the results were inconclusive because all we ever found were tunnels; no perp.

Whats eating my tomatillos

When I planted the tomatillos again, something, of course, started eating the leaves. I was more worried about fruit, and there was a lot developing amid the hundreds of yellow flowers. But the larvae on the leaves were far too fat to make the tunnels.

They did, however, enter the pouches through the tip and tear big holes in the tomatillos. And whatever minuscule varmint was making the tiny tunnels was in there doing the deed right along with those striped things.

It was time to kill everything that moved on my tomatillo plant, with the exception of the bees! I didn’t want to use chemicals, but soapy water wasn’t doing the trick.

Bug battles

In year three of my tomatillo battle, some leaf-eating bugs moved in again. Those were easily identified as three-striped potato beetles (more orange than a three-striped cucumber beetle). I armed myself with organic AzaSol, which will control all kinds of plant pests.

Of course, every time I sprayed, rain fell soon after, sometimes before the stuff could even dry. Fine. I resorted to smashing them. Bugs, eggs… everything but the bees.

Between my murderous frenzy and AzaSol (you can’t find them all once the plants are thick and huge), I finally succeeded in getting enough undamaged tomatillos to make that roasted salsa and green sauce. It only took four years!

Do you know what makes these pinhole tunnels?

The entry and exit are between a pinprick and a pinhead wide, many so unnoticeable the tomatillo looks fine until you cut it in half. Many don’t have any holes in the husk either.

The creatures tunnel straight through. Nothing is left behind. It’s a clean, precise passage. They never wander around. After making the tunnel, it moves onto a fresh one and repeats the process. And then it disappears.

You would think you could clean it up and use part of the fruit for instant cooking, but like an apple, it turns the inside of the tomatillo brown from exposure to air. There are no other visible exterior signs of rot or damage. The only bugs on the plants are these potato beetles.

Do you have the answer? Can you solve this maddening riddle? PLEASE SHARE!

Last updated by Catherine Sherriffs on 06/19/2020.

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23 Comments
  • Kelli says:

    After more research, I think what I have is tobacco budworm moth. So i am spraying with bacillus thuringiensis. It is an organic treatment for caterpillars that does affect bees. The extension service also suggested spraying with cyfluthin.

  • Kelli says:

    I captured one of the insects (looks like a tiny moth) and can send you the picture if you would think it might be your same pest. Just email me. I still have been unable to identify it, but will talk to the extension service next week to see what they can tell me. kdrobinson3@gmail.com

  • Kelli says:

    I have these pinholes also in my tomatillos. When I cut them open, there is usually an empty worm casing about 0.7cm long. A couple of times a 0.5cm skinny fly with white wings flew out. I don’t know what to do about them, but will continue to look at comments for suggestions.

  • Connie says:

    Great site! Thanks for your info, we have something eating our leaves on our young tomatillo plants. We have about 15 plants. Never had this happen before in MI or FL. We think it’s a beetle of some sort. They are devouring the leaves. Plants have yellow blossoms and not fully grown so don’t know about the fruit yet. Was anyone able to determine what the cause was? Appreciate the insight & info. We don’t want to use chemicals if possible. Don’t want to hurt our bees & other pollinators or hummers. It’s 2019 now and it appears to still be happening. Had a weird cool & rainy spring & still lots of rainy weather. Thank you.

  • Eliza says:

    I’m sorry no one was able to identify them for you yet. Most likely you have tomatillo husk worms, which are the same species as tomato fruitworms/corn earworms.

    You can treat them with Bt for moths which is far less likely to damage your pollinating bees than a broad spectrum pesticide (even an organic one). If it’s made to kill everything, that’s what it does, which leaves you as the sole protector of your plants because it takes out your pest’s enemies as well as the pollinators.

    Only 3% of insect species are pests, and most of the other 97% eat them. Additionally, pest insects are the “rabbits” of the entomological world in that their strategy to survive amidst so many predators is to reproduce like crazy so a few individuals pass on their genes to the next generation. This means a recently sprayed garden is a blank slate where the pests have an open window (usually half a growing season or more) to party hard destroying your crops before the predators show up and start eating them/reproducing their own kind to catch up. A mature organic garden full of biodiversity in plants and insects tends to balance itself out, but a new organic garden (especially in a neighborhood full of lawns or with a newly introduced vegetable that hasn’t had its pests & protectors show up yet) tends to have lots of problems. You reset to this “new” stage every time you spray broad spectrum pesticides instead of using targeted controls (or if your targeted controls are TOO successful and remove all the food for your predators.

    There are beneficial insects that will parasitize or predate your caterpillar eggs, larva, and adults,. However, they won’t come if there is nothing to eat, which means there has to be food present (aka, the pest) for them to build up their populations in your yard and keep it under control. Once they’re present, you’ll only lose a couple tomatillos instead of the bulk of them, which personally I find acceptable since I’m not having to spray all the time, spend money on pesticides, and happy tomatillos make more than I can eat anyway. You can achieve this by planting a sacrificial crop out of the way somewhere that you don’t try to control your pests on, by reducing how many you control (hand squishing is the best option here), or by sacrificing your main crop, which most of us aren’t interested in doing. Additionally, you need to ignore advice to sanitize your garden removing ALL the debris in the fall since your predators overwinter on the same materials as pests. Leave some winter habitat for your insect warriors.

    I also HIGHLY recommend planting flowers in the carrot (umbelliferae) and aster (asteraceae) families near your tomatillos (and other crops) because their blooms are beacons for the types of predatory insects you want. Herbs like cilantro, dill, and fennel are particularly excellent at attracting them. This is true of absolutely every crop that needs pollination or gets pest insect eggs & larva.

    Just make sure you deadhead the blooms once they start turning into seeds, because even though it still looks pretty to us at that stage, beneficial insects want a sip of energy-boosting nectar in between snacking on protein-dense pests and once the plant is making seeds it stops offering them this treat. Another good, inexpensive and fast-blooming plant for this is buckwheat allowed to flower. Good aster family options include zinnias and cosmos. You can use the dwarf ones if you don’t want them to crowd your veggies.

    The only pest insects I know of that don’t seem to have good predator controls no matter how long you use this strategy (on the southeast US coast at least) are harlequin bugs, leaf-footed bugs, and squash vine borer. I hand squish the first two or avoid growing the things the harlequin bugs like (mostly brassicas like kale/broccoli/etc.) in the hot months. It’s impossible not to grow things leaf-footed bugs like in the hot months. For squash vine borer I use Bt.

    If you’re interested in learning more about this type of pest control, look up the Living Web Farms videos on farmscaping, they’re great! I don’t usually leave long comments on old blog posts, but I’m a beekeeper and your comment on avoiding bee death sparked my interest. If my bees pick up a broad-spectrum pesticide in a garden and bring nectar it is laced with back to the hive to share, I loose a pretty big chunk of them (if it is something like Sevin dust stuffed into their pollen baskets it can even kill them all).

    Hope this helps. 🙂

    • Amber says:

      Hi Eliza,

      Thanks much for all that information, but I’m doubting that they’re tomato fruitworms. The damage inflicted doesn’t follow their MO at all! It’s a pinhole entry and a tunnel that goes straight through the fruit emerging on the bottom or the other side. No big gnarly chewing destruction. Sometimes the entry and exit are so small you don’t notice them until the tomatillo is cut open.

      Not only that – but there are tomato plants, and lots of them, just across the main central row without any tomato fruitworm damage at all! Whatever it is is attacking ONLY the tomatillos.

  • David says:

    Great site! Thanks! We have been able to identify our beetles with this info. We are in Big Bear City, California and never had these pests before we moved here. Here’s hoping for a good healthy harvest!

    • Amber says:

      So glad the article helped you figure out a solution!

      Happy to hear you like our website. You’ll find lots of great info for your gardening efforts here.

  • Patricia says:

    I have never had problems with tomatillos no matter where I lived except for some flea beetles. Now living back in NM with almost an 1/8 acre garden and the potato beetles are terrible on my tomatillos. And I have had potato beetles before but never on the tomatillos. And I love my roasted salsa verde! Arrrrgggghhhh!

    • Amber says:

      Hi Patricia,

      So sorry to hear you’re salsa verde is threatened. Arm yourself! Get some AzaSol. It works on many kinds of plant pests, and is approved for organic fruits and vegetables.

      Be sure to spray the whole plant – top and bottom surfaces of leaves.

  • Anna says:

    Well, add me to the list……I’ve got these little buggers on my tomatillo plant as well. Thanks for the information everyone; reading the comments has been great. I am determined to make salsa verde from my backyard this year!

    • Amber says:

      Hi Anna,

      So glad this page has once again helped someone. Salsa Verde, Roasted Salsa… there are just some things you cannot do without a pile of tomatillos!

      The AzaSol works great, and until you have it in hand, inspect the underside of all leaves every couple days for patches of those little orange eggs. Use physical pest control by smashing them between your fingers until you can spray for protection.

      Used this very method last year, and not one of the tomatillos harvested had those destructive tunnels!

    • Anna says:

      Thanks for the advice. Looking forward to getting rid of them!

  • Kristen says:

    Thank you for posting this. I am experiencing the EXACT same problem this year with my tomatillo plants, and now I am armed with a plan to combat the little buggers.

    • Tammy says:

      Hi Kristen,

      So glad to know I’m not the only person suffering from the invisible worm things destroying the tomatillo harvest. Hope the info helps you get the upper hand too.

  • Brenda says:

    This is going to sound CRAZY… but we are in the middle of our annual asian lady beetle infestation around our house and I SWEAR – Truly -the Asian Lady Beetles are eating my tomatillos! I thought they must be digging after something – but I am finding them face first in the open cracks of the fruit (where they burst from over water and ripeness) – no other insects or eggs in the fruit, just asian lady beetles digging in. I don’t get it?

    • Tammy says:

      That is odd, because they don’t eat fruit – but maybe they’re there for some other bug? Like fruit flies if the tomatillos are super ripe and splitting open. If there’s one thing a fruit fly adores it’s a dead ripe tomato, and tomatillos are closely related.

  • fred says:

    I had serious worm infestation with my tomatillos. I provided a couple of the worms to the local ag extension office and they were identified a tomatillo plant grubs. I used combination of perm-up and sevan to keep them under control. Got a lot of tomatillos. I have pictures of worms – both are less than an inch long. One is green with black stipes running on either side. the other is darker – more brown.

  • Linda Rendtorff says:

    Try this: It might be that a bug lays its egg inside the tomalito, the egg hatches into a larvae which eats its way through the fruit and emerges as a nymph or adult which then goes through several instars (insect growth stages) to become the egg-laying bug, and it all begins again. If that is the case, you may only see the ‘worm’ while it is inside the fruit, not on the outside. Good luck, Linda.

    • Tammy says:

      Hi Linda,

      This possibility has occurred to us, but the tunnel has two openings – one of each end! The creature enters, crosses, and exits. There is no hollow spot where something grew in there. Just a thin little tunnel that goes straight through and large enough to let air in that spoils the entire fruit.

  • Cheryl Perry says:

    Hi

    I’m having the same thing happen to me this year. Four years ago, I grew tomatillos from seeds with no problems. This year, i bought two plants instead of seeds. It didn’t take them long to have loads of blooms on them but then I started seeing the pin holes on what seemed like every tomatillo. So I made a spray from pureed jalapenos, cayenne pepper and water to use on the plants. It did not help at all. So I abandoned the plants because I never saw what was doing the damage.

    Yesterday, I went out to the garden and saw a few tomatillos that seemed undamaged so I got excited and picked them. Sifting through the hundreds of fruit on the ground, I picked up one and pulled back the husk and that was when I saw the worms burrowed in the tomatillo. I don’t know what kind of worm but they were short and striped.

    Does anyone have experience with this pest problem and are there ways to be more proactive for next year? I consider this year’s crop a loss. Any suggestions would be GREATLY appreciated!

    • Tammy says:

      Hi Cheryl,

      Don’t spray hot pepper juice on edibles! The plants can absorb it and altering the flavor of your harvest – an issue known to happen with pepper and garlic spray for deer repellents.

      Get some AzaSol. It isn’t cheap, but it does work on most plant pests, and is safe for organic fruit, nut, and veggie production. You’ll find it available from a handful of hydroponic shops online. Just price shop it. It goes a long way.

Author

The garden played a starring role from spring through fall in the house Amber was raised in. She has decades of experience growing plants from seeds and cuttings in the plot and pots.