Cotesia congregate Braconidae cocoons attached to this hornworm caterpillar (left) discovered on Little Eva’s tomato plant. Audlt Braconid (right) is generally less than 1/2″ long and do not sting people.
Order: Hymenoptera is the same order as ants, bees and other wasps. Braconidae are popular “biological pest control agents.” Each white oval in the photo is actually a wasp in its pupae stage (cocoon).
We discovered this hornworm caterpillar crawling on one of Little Eva’s tomato plants in the garden bed at the Outpost last August. The caterpillar had been feasting on the plants’ leaves, stripping it to its skeleton.
The adult female wasp located the tomato plant, then used her antennae to locate the host (caterpillar). She then used her ovipositor, a tube through which eggs are laid just under the skin of this unlucky hornworm. As the eggs hatched, the larvae fed on the hornworm’s viscera-literally eating a hornworm alive (parasitoid). Larvae chewed their way out through the host’s skin when they matured and pupated (spun a cocoon).
If YOU find a caterpillar that has these Braconid cocoons this summer, set it aside so these beneficial insects can mature. By the time the adult wasps emerge from their cocoons, the already weakened hornworm caterpillar will die a natural death, and the adult wasps will go off to search for other hornworm caterpillars to invade.