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Making Peace with Hornworms

August 27th, 2010

When I first started growing tomatoes I used to pick off the tomato or tobacco hornworms and squish them with a rock. Then one year I missed one and spotted it with the tiny white eggs from a parasitic wasp on it’s back. Ever since then I’ve made peace with the hornworms in my garden. I never pick them off or do anything to get rid of them. They get to eat some tomatoes leaves and a tomato here and there in complete peace. Why the change of heart?

I don’t want to get rid of them and risk the parasitic wasp not having a host for it’s eggs. I also don’t want the birds to go hungry, as they seem to find these giant juicy worms a complete breakfast. The truth is they’re not that damaging to tomato plants. Perhaps a little defoliation is good for tomatoes this time of year and I don’t mind losing a couple tomatoes, I have plenty to go around. The truth is that often when we step in we upset the balance of nature and make our problems worse down the line. If we squish or kill all the hornworms we’ll never have the braconid wasps in our gardens. Without the wasps we’ll end up with more hornworms, aphids and other insects. We may also inadvertently kill a hornworm that has already been parasitized by a wasp since it takes a few days before the white worms appear on their backs.

I’m convinced that I’m encouraging biodiversity in my garden by making peace with hornworms and other things viewed as “pests”. I have noticed that the less I interfere with nature the more balanced things become, even in my small quarter acre garden. I encourage you to let the hornworms live and see how everything balances out in a few years!

Do you have any pests that you’ve made peace with?

Here’s an interesting article from the BBC about how plants can send out SOS signals to predatory insects when they sense they’re being attacked by caterpillars & other insects. And the specifically studies hornworms.

18 Comments to “Making Peace with Hornworms”
  1. Allie on August 27, 2010 at 4:52 am

    Wow! They’re kind of gorgeous, really.

    Reply to Allie's comment

  2. Norma on August 27, 2010 at 5:30 am

    Yes definitely! Aphids! I leave them to my roses and hibiscus to the shock horror of visitors, but every year am rewarded for my patience with more and more ladybirds:)
    The plants don’t mind after their initial shock and look great once the ladies arrive.

    Reply to Norma's comment

  3. Christa on August 27, 2010 at 7:56 am

    I have a lot of hornworms in my garden this year. I was picking them off until you explained in one of your comments that you don’t do that for the purpose of feeding birds… So I decided to leave them. It’s hard but I’m doing it. Thanks for sharing.

    Reply to Christa's comment

  4. megan on August 27, 2010 at 9:28 am

    I do this, too. Hornworms can get so huge! I’ve only had one plant that was stripped completely–a potted tomato that was basically a sitting duck. Other than that, they don’t seem to do too much damage. And, in addition to attracting beneficials and feeding the birds, it’s a lot less work!

    Reply to megan's comment

  5. Mary W on August 27, 2010 at 9:35 am

    Normally, I share your attitude, but our tomatoes were decimated by hornworms this year. I’ve never seen anything like it. But it’s a public plot and I think it was heavily medicated by the previous gardener. We’re suffering the backlash. Next year we’ll plant a lot of flowers and try to get the beneficials and birds back. That reminds me, I need to add this to my lessons learned list!

    Reply to Mary W's comment

  6. Paula on August 27, 2010 at 9:40 am

    I agree and disagree with you. The hornworms set in before the tomatoes have even set fruit in my area. They will strip a plant bare. This year, we were really busy with baseball and I had been keeping an eye out for those buggers and saw the evidence and the destruction. My kids are excellent at spotting them, I always miss them, so they were picking them off. A few days went by and I see more damage, but I got distracted and forgot about it. There wasn’t any more damage, because a family of wrens moved in and had a clutch that hatched. They ate the hornworms as well as the cabbage worms that were eating my okra plants!

    I don’t think we have any of those parasitic wasps here, I’ve never seen anything like that before.

    Reply to Paula's comment

    • Susy on August 27, 2010 at 9:47 am

      Wrens are wonderful to have around for caterpillar control, they do wonders with cabbage loopers.

      Reply to Susy's comment

  7. Jennelle on August 27, 2010 at 10:11 am

    Those stupid hornworms ravaged my tomatoes this year! I didn’t kill any, but I pick a few off and tossed them in the grass… I suppose I figured they’d just find their way back. I ended up picking all my tomatoes that were left green and I’m going to pickle them. I guess when life gives you tomato hornworms, you make pickled green tomatoes, right?

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  8. Jaspenelle on August 27, 2010 at 11:03 am

    Aphids, the week I decided to ignore them, ants moved in and carted them off to my biggest sunflower, which can handle it, to “farm”. When the population started getting scary big (but still on that one flower) I found tons of ladybird beetles on it on morning, culling the herd.

    My neighbor has a huge aphid problem right now (and I’ve none) I’m thinking it is because her pesticides kill all the beneficial too. Funny since it isn’t killing the aphids.

    Reply to Jaspenelle's comment

  9. Miranda on August 27, 2010 at 11:46 am

    Interesting. I”ve never seen braconid eggs in my garden – but i do have some paper wasps that eat the hornworms. I still pick them off though – feed them to the chickens. The chickens love them SO.MUCH. that it’s hard to resist tossing that lovely treat to them. Perhaps i’ll leave more worms in teh garden, but with only 1 producing tomato plant right now – i can’t afford to lose a single tomato, even to promote biodiversity.
    I HAVE been leaving more leaf footed bug nymphs than i used to – they used to be on the ‘no mercy’ list. But i have so many anoles that live in the garden, and i believe i’ve seen them stalking the young leaf footed bug nymphs – so i leave the babies for the lizards to munch on. I still enjoy slicing the adult stink bugs in half with my pruners in the morning: mwa ha ha ha.

    Reply to Miranda's comment

    • Susy on August 27, 2010 at 2:10 pm

      Yes, I always plant a few extra tomato plants just for the hornworms.

      Reply to Susy's comment

      • Miranda on August 27, 2010 at 2:22 pm

        Ah, i do have one crappy dying non productive plant i could just move them too. Great idea, Susy! Buffer crops are where it’s at.

        to Miranda's comment

  10. Jackie on August 27, 2010 at 2:37 pm

    I’ve made peace with aphids this year. Their numbers haven’t been very high and the parasitic wasps (bless them!) have mummified so many of the aphids that they never got out of control. High fives to the wasps and chickens for keeping things in check this year!

    Reply to Jackie's comment

  11. Debbie on August 27, 2010 at 4:51 pm

    I haven’t found any hornworms this year (and we have 19 tomato plants) but one of our plants looks similar to yours – only it never got very tall either. We do have aphids and beetles and other sorts of caterpillars and I just leave them all. I don’t have it in me to kill a living thing – and as long as there’s lots left for us…I’m fine. Pesticides would never be an answer for me either – they are so contridictory in nature. In the long run – they don’t work. Nature will balance itself out if left alone. i truly believe that.

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  12. Christa on August 27, 2010 at 5:36 pm

    I know this must sound silly but I just went down to my garden and there was a hornworm with those white little things all over him. Yeah!

    Reply to Christa's comment

  13. Ryan on August 27, 2010 at 8:15 pm

    This is a great post. I was thinking of your garden posts while I was puttering about my garden this evening. You are one of many of my teachers and this is definitely another lesson to add to the list! I keep giving the hornworms to my chickens but I wouldn’t mind leaving a few around in the future — Thank you for the new outlook!

    Reply to Ryan's comment

  14. nic@nipitinthebud on August 29, 2010 at 3:02 am

    I’ve never heard of hornworms, glad we don’t have them here. I’ve made peace with cabbage white caterpillars. Had hundreds last year and after spending a couple of hours picking them off the white fly population exploded in numbers. Ants have devoured some root vegetables but they helped manage the black flys on the beans and the soil is always lovely and loose where they take up residence.

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  15. Karla on August 3, 2011 at 12:40 pm

    Aren’t you interfering with nature just by planting the tomato plants? They’re not native to Ohio.

    Reply to Karla's comment


This is a daily journal of my efforts to cultivate a more simple life, through local eating, gardening and so many other things. We used to live in a small suburban neighborhood Ohio but moved to 153 acres in Liberty, Maine in 2012.

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