looks like Tomato hornworms - probably should get them off of your plants. Here is some info

Here is a link that might be useful: u of minnesota extension site

Normally on the butterflyforum, we don't recommend "getting rid" of caterpillars. The caterpillars on your tomato plants are Tomato hornworms, but they become a moth that pollinates plants. Best way to treat them is to plant spare tomato plants and keep the caterpillars on those plants. I did this earlier in the season.

Here is a link that might be useful: Five-Spotted Hawkmoth

Please don't use quotes unless you are going to actually quote me. I said the OP should get them off their tomato plants and gave them a link that explains what else they would eat. Most people plant tomato plants in order to eventually eat tomatoes. Since the OP didn't know what had appeared on their tomato plants, I made the leap that they fit this category.

thanks, they are actually Tobacco Hornworms. I picked them off and put them in a container with holes and leaves so the kids can watch them.

Kids think they are the coolest things. They will actually winter over under the ground exactly where your tomatoes are planted--makes it more convenient for finding their host plant next year.

cdsetx8,

You may not have said "get rid" of them. However, the link you posted tells ways to dispose of them and chemicals to use including BT.

Sorry you were offended by my comments, but your posting left me with the wrong impression.

njmomma, the kids will love watching these guys. The moths are cool. I've raised them in the classroom. Put about 4 inches of soil in a clear container, cover with the leaves, and you may be able to witness them forming pupae through the sides of the container. An old 2 liter pop bottle with the top cut off works great.

I toss these big guys (Tobacco hornworm) to the birds when I find them munching on my tomatoes. Even just one can do a lot of damage. And there's never just one. If you are growing just a few tomato plants for fresh eating, this might be considered one of the 'bad guys' in most estimations. But no chemicals are necessary.

BTW, those 'horns' aren't dangerous. These caterpillars can be handled without any problem.

butterflymomok

Truce. We're on the same team :)

I started growing "sacrificial" tomato plants years ago, after encountering my first (but unfortunately parasitized) hornworm. Haven't seen one since :(

Wow, have you guys never even seen a Hawkmoth? One of the coolest moths ever. When I was 5 I thought one was a hummingbird. And by the time the caterpillar is 4" long it has about finished eating tomato leaves anyway. Most tomato plants sucker like mad and have way too much foliage to boot. Ain't nature grand, except in your own backyard. I unfortunately haven't seen one for years.:-( And the caterpillars are spectacular, too.

Don't the tomato hornworms turn into sphinx moths?
I have those hornworms all the time. You just learn to do "border patrol" at your tomatoes every day. I just pick them off and put them in a bush away from the garden.
I've had them click at me and bend their heads back towards my fingers. Its a little scary. haha But they don't hurt.
I think they're cool. But you do have to look for them everyday, so you can catch them before they eat much. They are so well camouflaged. I usually look for their square, segmented poop and that leads me to them.