These tiny fly predators are nature’s first line of defense against nuisance flies — including the common housefly. The female predator seeks out a host pupa, drills through its cocoon, and lays several eggs inside it. The resulting parasitoids kill the pupa by consuming it.

The adult stage of this popular biological fly control emerges from its host after two or three weeks to seek out other pupae for its eggs. By destroying filth flies before they can reach the adult stage and lay more eggs, these gnat-sized parasites play an important role in controlling flies around manure piles, chicken coops, corrals, garbage sites or any other place that might harbor flies and their maggots. They are best introduced in early season, before pesky flies have had a chance to flourish. The tiny parasitic wasp does not bite or sting and is harmless to humans, plants and animals.