Garden · Homeschool · Kids · Nature Study · Pests

Hornworm Experiment

Each summer we pick through our tomato and pepper plants looking for hornworms. This has been the best summer yet. I found the only one this year as I was ripping out all my tomatoes. The battery in my irrigation timer died when we were out of town and they took a beating in the July heat. Everything else recovered just fine but the tomatoes were fried. I was thrilled that I made it through the main tomato season without a single hornworm!  So, I made sure to show the girls this one.


Tomato Hornworm
Tobacco Hornworm – Manduca sexta

This is actually a tobacco hornworm.  It has 7 diagonal strips and a red horn.  No, I’m not growing tobacco…these guys feed on tomatoes as well.  Here’s a great video that describes the two big differences between tomato and tobacco hornworms.

This guy was huge! We put it in a bug catcher cup with a magnifying glass top so they could see it up close. I was thinking it would be a great way for them to look at it while drawing it in their natural journals. However, the girls had something else in mind. They wanted it to put it in our butterfly habitat and let it turn into a moth. Really?! These things can destroy a tomato or pepper plant in no time. As a gardener, it made me just cringe to think we were going to help it complete its life cycle. But how could I say no to the girls wanting to see this?

The next day I went out to cut some fresh tomato leaves to feed the little pest but it didn’t seem at all hungry. I put a container of garden soil in the butterfly habitat so that it could burrow down to pupate. Less than five minutes after I put it on the soil it headed under. Luckily, I saw it at the last minute and managed to get a photo of its tail sticking out. Unfortunately, the girls were gone that morning.


Tomato Hornworm burrowing to pupate
Tobacco Hornworm burrowing to pupate

Several weeks later, Comedian and I were outside when Storyteller came running out yelling. The moth had hatched! It happened so quickly. The wings were still wet and shriveled. We watched over the next hour as they dried and expanded. They were really surprised that it was so big! We let it go the next night and watched it fly off.


Tobacco Hornworm Sphynx Moth

They are excited to find more so that we can continue to hatch them. I’m glad we were able to experience it but I think I prefer giving them hot soapy baths. The things we do in the name of science and nature for our kids. Sigh…



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