Of all the pests that plague tomatoes, I think most gardeners would nominate the Tomato Hornworm, the caterpillar that turns into the magnificent Five-spotted Hawkmoth, as about the worst of the worst. Hornworms are veritable eating machines, and a single caterpillar can lay waste to an entire plant in record time. The fact that this garden carnage leads to a gorgeous adult that behaves like a hummingbird does not, typically, lead to tolerance, but much of the time, gardeners don't have to do much. Nature takes care of matters on its own. Oftentimes, small parasitic wasps known as braconids will lay their eggs on Tomato Hornworms, and the wasp youngsters will eat their way inside the caterpillar, eventually killing it before emerging to start the cycle anew. With any luck, this macabre parasitism will keep the hornworms in check, enabling us to enjoy tomatoes and the occasional hawkmoth.