Suppression of House Flies (Diptera: Muscidae) on New York and Maryland Dairies Using Releases ofMuscidifurax raptor(Hymenoptera: Pteromalidae) in an Integrated Management Program

Abstract

Releases of Muscidifurax raptor (Girault & Sanders) were integrated with weekly removal of calf bedding and infrequent use of pyrethrin space sprays for management of house flies, Musca domestica L., on seven dairy farms in New Yorkand Maryland; six other farms were used as controls. Baited traps were used for supplemental outdoor fly control on release farms in Maryland. Parasitoid releases were made by weekly placement of either 25,000 (in New York) or 20,000 (in Maryland) parasitized house fly pupae in screen bags on each farm, resulting in weekly release rates of 12,000 and 9,600 female. parasitoids per farm per week, respectively. Overall season-long fly pupal mortality (as measured by sentinel fly pupae) was 65 and 38% on release farms in New York and Maryland, respectively, compared with 30 and 26% on control farms. Overall parasitism was 36 and 18%on release farms in New Yorkand Maryland, respectively, compared with 5 and 3% on control farms. Fly populations on control farms in both states were approximately twice as large as on release farms based on spot card and resting fly counts inside the barns. Producers on control farms in New York made an average of 14.7 insecticide applications (space sprays, baits, and residual premise treatments) for house fly control compared with 2.7 insecticide applications (pyrethrin space sprays) on release farms.