By Dr. Stuart Mitchell
Mechanically moving pathogens from filth to agricultural enterprise, House flies, Musca domestica, cause distress and spread disease on poultry and livestock operations. Within the IPM template there are numerous controls for fly pressure. However, one very effective agent that can be employed in the process of pest pressure reduction is Parasitoids or parasitic wasps. A Parasitoid is an animal (insect) that is parasitic during its larval stage. The adult stage is free-living.
Enhancing the efficacy of judicious and intuitive professional product use, diagnostically selected parasitic wasp species can be employed as a biological control to further reduce fly pressures.
Muscidifurax raptor (meaning "robber-thieving fly") is one surgically effective parasitic wasp available from commercial rearing insectaries. Emerging from the pupal stage as adult wasps, dispersal results from protected release stations suspended from elevated locations.
Muscidifurax raptor wasps on fly puparium. (Image credit: USDA-ARS)
Releasing their progeny into Muscoid flies, female wasps aviate into the agricultural theater. Specifically locating pupal stage flies (the puparium), Parasitoid females insert their ovipositor then extract it, drawing fluid and paralyzing the pupa. Female and male wasps ingest some fluid.
A combination of feeding and stinging may kill the pupa. If determined to be a fit host for progeny, the female wasp places one ova within a pocket under the puparium. After approximately 24 hours, the wasp larva emerges from the ova, and for 2 to 4 weeks proceeds to feed upon the host's organs and fluids. Masticating out of the puparium, the adult wasp emerges and aviates.
Holes in House fly puparia resulting from single wasps emerging.
(Image credit: USDA-ARS)
As a challenge to commercial insectaries, wasps are occasionally infected with the Genus Nosema microsporidium. Pathogenized Parasitoid wasps require longer developmental time. As a result, adult females place a balance of male ovum, which drastically reduces yield of attacking female wasps.