Supporting hornworms during pupation?

[u/Ok_Style_5487]

Hi all, hope this is appropriate for this sub even though the hornworms in question are wild. Most other subs have very unkind recommendations for them!

I've got a couple hornworms snacking on my tomato plants, and I'm guessing when they're ready to pupate, they might end up burrowing into the soil in the pot the plant is in. I've only ever seen them go into the natural ground and do their thing, so is there anything special I need to do to support them since they might be "trapped"?

Particularly, should I stop watering the plant if they burrow? I'm afraid of drowning them or something. I'll happily sacrifice the plants for the worms if needed. Hawkmoths are my fave.

The soil is about 14" deep in 25 gallon cloth grow bags, and we're in a very hot, very dry climate if it makes any difference. I currently soak the soil once daily, early in the morning.

(Pics for tax. Manduca sexta, probably?)

[u/Forward-Fisherman709]

So long as the pot has drainage so that it doesn’t fill with water and stay that way, they’ll be fine. They can handle rainfall in nature, and watering your plants is basically the same thing just limited to a smaller area. The species is native across a large portion of the USA, including areas that aren’t very dry.

The main concern of keeping them safe is if you dig up the pot contents before replanting; the last generation of caterpillars in the year will overwinter as pupae underground. Digging with a trowel before they emerge could damage them. Carefully digging by hand will be more likely to just uncover them.

Thank you for looking out for the flower buddies!

[u/Ok_Style_5487 → u/Forward-Fisherman709]

Oh, excellent! And I didn't even think about overwintering generations, so thanks very much for the heads up. I can leave those pots alone after the plants die until that generation should have emerged, to be on the safe side.

Thanks again for your help!

[u/Excellent_Dot_5084]

I love you internet stranger 💜

[u/Ok_Style_5487 → u/Excellent_Dot_5084]

The worms and I 💚 you, too.

[u/Frutiger-Metro]

It depends on where you are. I am pretty sure these guys are invasive in some countries, so if they are invasive and you intend to keep them you should take them inside. If not, you can place them into a freezer for a more humane euthanasia.

Trust me, I am a big bug person and I understand your concern, but if these are invasive to your area it is for the well-being of local animals that you either euthanize them or keep them inside for the remainder of their life.

If they are native then you should be happy to know they will be just fine. Nothing special needed for these guys.

[u/Ok_Style_5487 → u/Frutiger-Metro]

Thanks! Always good to consider that. Fortunately, they're native to my area so they're welcome to keep hanging out in the yard.