Trichogramma wasps sold commercially are parasites of cabbleworm, tomato hornworm, corn earworm, codling moth, cutworm, armyworm, webworm, cabble looper, corn borer and almost all moth and butterfly eggs that hatch into worm pests. Host eggs turn black with the newly hatched wasp larva moving within the host egg, killing the embryo. Larvae hibernate in the host egg with the number of broods varying from 13 to 50, depending on climate. One or more eggs are deposited in the body of an aphid, but only one develops into a mature wasp. Larvae, as an internal parasite, consumes all but the skin.
Body juices ooze from the aphid, gluing it to the twig.
Aphid shells become black and mummified. The life cycle is about 30 days. Hosts include woolly apple aphids, cabbage aphids, greenbug, rose aphids and other aphids. These wasps are entirely black or black and red, clothed with a fine pubescence. They are parasitic in the egg capsules of cockroaches.