Tolypocladium cylindrosporum, a novel pathogen for sheep blowflies

Dead larvae and pupae of the sheep blowfly, Lucilia sericata, were collected from field soil and subjected to pathological examination. A haemocoel sample of each cadaver was screened for pathogens by growth on specific media, and dominant isolates were characterised with biochemical and morphological tests. Thirty-eight bacterial and 15 fungal isolates were isolated and bioassayed against L. sericata larvae in soil. Nearly all larvae challenged with microbes survived to emergence of the adult fly, but two Tolypocladium cylindrosporum isolates caused a 100% reduction in emergence. A selected isolate was further tested against larvae of L. sericata, L. cuprina, Calliphora stygia and Chrysomya rufifacies, and there was strong suppression of adult emergence (0-20% emergence) compared to untreated controls (93-100%).