Beauveria bassiana and 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 domestica L., 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. bassiana formulated in water and a surfactant (Tween 80) was evaluated for the control of house fly adults. The prevalence of B. bassiana in the adult fly population was significantly greater in hutches sprayed with conidia than in untreated control hutches. Maximum weekly recovery of B. bassiana was 43 and 47% of the collected fly populations at two treatment farms. A second mycosis caused by Entomophthora muscae (Cohn) Fresenius developed to an epizootic in untreated and treated fly populations. Combined mycoses from B. bassiana and E. muscae reached 60 and 54% of the fly population on two of the treatment farms. The prevalence of E. muscae reached 70% in the fly population on the control farm