Mainers have found a powerful ally in the annual battle against tomato hornworms.
Tomato hornworms destroy plants before the fruit even has a chance to ripen. They are a common, albeit unwelcome, pest that feed on plants including eggplants, pepper plants and tomatoes. In Maine, they seem particularly fond of the tomatoes and thanks to their voracious appetite, they can strip a plant clean almost overnight.
But the braconid wasp — a tiny, parasitic insect — can kill hornworms almost as fast as the worms themselves destroy a tomato plant. Otherwise, the only way to eradicate hornworms is by picking them off your tomato plants one-by-one. It’s good news for gardeners who are experiencing a particularly bad year for the hornworms.
The adult female wasp will sting the hornworm and lay her eggs inside its body, according to Jim Dill, pest management specials with University of Maine Cooperative Extension. The wasp larvae develop inside the caterpillar and eat their way out, killing the hornworm in the process.
“While they are developing inside the caterpillar, the wasp larvae are slowly making it incapable of doing anything,” Dill said. “They are basically turning it into a mummy.”