There are three things you can do to rid your tomato plants of tomato hornworms that don't require you to touch the hornworms.
1. Interplant dill or borage with your tomatoes. The moths that lay the eggs that hatch into tomato hornworms don't like dill and borage so they will fly away and lay their eggs elsewhere.
2. You can plant flowers and herbs that have tiny flowers amongst your tomatoes. Beneficial insects that kill hornworms like plants with tiny flowers so they will be attracted to those plants and lay their eggs nearby or even on the hormnworms themselves.
3. Till your garden twice a year, once in the fall and then again in the spring. This will kill any larvae that are hibernating in your garden during the winter. Fewer larvae means fewer moths to lay eggs that will hatch into hormworms.