Organic Tomato Hornworm Control

Tomato Hornworm Guide

If you see a hornworm with white oblong sacks on its back, do not destroy it! These are actually the cocoons of a parasitic wasp, called the braconid wasp. A female wasp has laid her eggs under the skin of that hornworm. Once they hatch, they feed on the insides of the caterpillar. The larvae then eat their way out of the caterpillar to spin cocoons on its back. Adult wasps will emerge from the cocoons, and the weakened hornworm will die. The hope is that the emerging wasps will find other tomat