tobacco, tomatoe, bell pepper etc. are all host plants of the wild hornworm and they are all the same larvae, catterpillar, whatever, you should never feed them from the wild, people order from places like mulberrryfarms glhornworms etc because they have special cultures that make them safe to eat and a great feeder on occasion. Hope that helps you out a bit.
Both tomato hornworms and tobacco hornworms are used as feeders. However the ones used as feeders have been captive bred on diets that do not contain the toxins found in tomato or other solonaceous plants. About the only part of the tomato plant that isnt toxic is the tomato. The poison from the tomato or toabacco plants do not leave the larva, so even if you took babies off tomato plants and fed them a toxin free diet they would still have the toxins they got from when they did eat tomato plants, They just wouldnt get more. Once they have eaten tomato at all they should never be used as feeders.