Beauveria bassianaand Sawdust Bedding for the Management of the House Fly,Musca domestica(Diptera: Muscidae) in Calf Hutches

Beauveria bassiana(Balsamo) Vuillemin was used concurrently with sawdust bedding to manage the house fly,Musca domesticaL., in calf hutches on New York dairy farms. Sawdust bedding was compared with straw bedding for larval development. The number of fly larvae recovered from bedding samples was lower in hutches bedded with sawdust (53/liter) than in straw bedding (131/liter).B. bassianaformulated in water and a surfactant (Tween 80) was evaluated for the control of house fly adults. The prevalence ofB. bassianain the adult fly population was significantly greater in hutches sprayed with conidia than in untreated control hutches. Maximum weekly recovery ofB. bassianawas 43 and 47% of the collected fly populations at two treatment farms. A second mycosis caused byEntomophthora muscae(Cohn) Fresenius developed to an epizootic in untreated and treated fly populations. Combined mycoses fromB. bassianaandE. muscaereached 60 and 54% of the fly population on two of the treatment farms. The prevalence ofE. muscaereached 70% in the fly population on the control farm.