Reptile & Amphibian Forums

Hi there,
Yesterday, I found an enormous green worm on a tomato plant... I've never seen one quite like this before. I have definitely identified it as a tobacco hornworm. That's where my internet research reached a dead-end... but my kids (7, 8 & 9) are thrilled at the prospect seeing it through moth stage.

Would this be feasible? Right now it's in a mud-bedded spaghetti jar with some small green tomatoes for food. Wow, what an eater this creature is! It must consume its weight in fruit within a few hours! If I try to supply enough fruit to keep up with its appetite, I'd be giving up my own supply of tomatoes. The worm is about 3.5 inches long and the diameter of penny.

Any suggestions for homebrew rearing? Alternative items it might eat (other than my tomatoes!). I did find instructions for a rearing chamber, made with a 2-ltr bottle, soil, and a popsicle stick - but can't use it until the worm enters this "wandering" stage. When will that happen??? HELP, PLEASE. Thank you! -Vix

Hey, don't wast your tomatoes on this little guy, unless of course, they are cull fruits. feed it leaves, instead. Honestly, it got that big by eating the leaves and small stems. Also, you need to put it in a larger container......along with about 6" of soft, slightly moist [but not wet] soil.
Your larva is full grown and will stop eating soon. it's ready to pupate any time, and just prior to pupation, it will stop eating, become restless and even lose weight. Don't let this alarm you. It has to lose it somehow, because adult moths are just never nowhere near that big. most likely, this late in the year, the pupa will overwinter and eclose as a pretty moth next spring. it will be bark colored and mottled gray, with six orange spots down each side of its abdomen. It's a handsome and very beneficial moth. It pollinates a lot of flowers other small moths or butterflies can't.

Cool! Thank you for your help. A few more questions...

I've read on various websites that the moth will emerge in about 3 weeks. You say it will take all winter. That's a long time. Will there be any way to know if it's still alive? Is there any movement at all during its change?

I will move it into larger quarters, but am wondering if it should be kept in the house after it burrows into the soil, or should it be out in the garage and endure the cold temperatures which are soon on their way?

Finally... Hygiene. This larva produces an incredible amount of poop. Am I supposed to clean the cage out or change the soil at all?

Thanks again for your help! My kids are so excited about this!

Yes, you need the keep the frass [droppings] removed daily, as these will mold and could kill the caterpillar. Now if that moth does not emerge within 3 weeks, it may overwinter. A live pupa will sometimes move a bit if very gently squeezed. Otherwise, you can touch the head or the pupa to your nose or even edge of your lip to feel its temperature. A coolness will usually indicate life while a room temp or not as cool one, may be dead.