Enemies and Allies: Hornworms and Wasps

“The enemy of my enemy is my friend.” This ancient sentiment applies very well to the denizens of the garden. The tomato (tobacco) hornworm in the pictures is a being of great tomato destruction. This larval stage of the five-spotted hawkmoth is able to demolish whole tomato plants in a matter of days if not caught early. It feeds off the tomato plants with a voracious appetite leaving behind bare stems where green foliage used to be. But there is help on the way for the organic gardener. Without using pesticides you can rely on Mother Nature to provide a counter attack for these destructive beasts.

Enter the braconid wasp! And I do mean enter! This parasitic wasp lays it’s eggs inside the hornworm where they hatch and eat their way through the flesh of the hornworm. The wasp is harmless to people and animals but is a death sentence to the hornworm. The white shapes covering the hornworm in the pictures are the larva of the wasp working their way out. If you see a hornworm in this stage it is best to let it be and let the braconid wasps do their work. The wasps will continue to grow then lay their eggs in other hornworms which will protect your tomatoes from being unceremoniously snacked upon.

If the wasps haven’t assassinated your enemy then you can easily pick up and dispose of the hornworms in a solution of soapy water.

R.I.P. Tomato Hornworm

16 thoughts on “Enemies and Allies: Hornworms and Wasps

  1. Gail

    Wow, I have wondered what the parasitic wasps looked like…thanks for the image! We (I) get excited about moths and caterpillars and forget that the Tomato Hornworm is on its way to being a sphinx moth!


  2. Anna

    The hornworm alone is enough to scare you and then add those wasp babies—it really does look savage. That poor hornworm probably wishes you’d come out from behind the camera and help a guy out.

  3. Dave

    I’m shocked to hear some sympathy for something trying to eat my tomatoes! 😉 OK I’ll admit it probably wasn’t pleasant for the caterpillar. It’s not real pleasant to look at either but Mother Nature works in amazing (if sometimes somewhat gruesome) ways!

  4. hap

    I had read about the wasp larva destroying the hornworms but have never seen a picture. That’s a great shot. The wasp larva eating the hornworm is easily my preferred method of elimination.

    It would have been nice if the larva would have gotten to the hornworms prior to them eating my cherry tomato plant. At one point there were three huge hornworms having a feast on the plant. Their presence will not go unnoticed next time.

  5. Dave


    I missed your last comment! Sorry 🙂 Do you have a picture of the worm? I may have similar one’s in our garden.


    Yuck is fairly accurate!


    They are very hard to see among the foliage of the tomatoes. These particular worms climbed to the top of the tomatoes otherwise I might not have noticed them. I think the best thing you can do is plant enough tomato plants so that what damage they do can be easily replaced by the other plants.

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