While I haven’t seen any tomato hornworms in my garden, I have viewed some postings and photos of home gardeners dealing with the hornworms. Tomato hornworms aren’t worms. They are the larva stage of the five-spotted hawk moth. The hornworms feed on the foliage of the tomato plants, removing leaves that produce nutrition and energy for the plant and provide sun protection for the fruit.
The tomato hornworms are sometimes difficult to locate on a plant where symptoms of feeding are easy to see. Don’t give up! Look very closely!