This is not, strictly speaking, a tomato worm. It’s the larva of Manduca sexta, the dreaded Tobacco Hornworm. Nor is it a worm. It’s a larval insect that could more properly be termed a caterpillar if not for the image of caterpillars being cute and worms being ugly. Anything capable of stripping the leaves of a full grown tomato plant is certainly not cute!
Tomato hornworms do exist. They are the larvae of the Five-Spotted Hawkmoth (Manduca quinquemaculata), cousin of the Tobacco Hornworm (M. sexta). Both devour tomatoes, so neither you nor your plants will probably care that Tobacco Hornworms have red horns instead of black, and seven diagonal lines instead of eight “V” shaped markings. I suppose that’s why they named the creature “sexta“, so every Latin speaking gardener could easily keep things straight.
Though you may find them useless, it’s possible that these facts could earn you a free beer in a barroom bet. If you’re really bored, it could be worth a try. Plopping down a three inch worm on a bar counter and declaring it not to be a true quinquemaculata tomato worm but instead a Manduca sexta should be good for at least a free pretzel stick. Don’t try this in an entomologist bar though. It’s been done to death and you’ll probably wake up lying on hot asphalt, covered with worm spatter.
A friend told me to treat everything with Bacillus thuringensis (BT), but then I’d have no worms to photograph, no stories to tell, and no way of getting free beers in the local bar.