Entomopathogenic fungi in flies associated with pastured cattle in Denmark

Cattle flies, including Musca autumnalis, Haematobia irritans and Hydrotaea irritans are pests of pastured cattle. A 2-year study of the natural occur rence of entomopathogenic fungi in adult cattle flies and other flies assoc iated with pastures showed that the four species included in the Entomophth ora muscae species complex (E, muscae sensu late) caused high infection lev els in several species of dies, However, only a few specimens of cattle fli es were infected by E, muscae sensu stricto despite the fact that cattle fl ies were observed to perch on spear thistles, which acted as transmission s ite for all four Entomophthora species. Transmission experiments with E, mu scae s.l supported the field data. Of the two species considered host speci fic, E, syrphi caused substantial infection in a muscid, and E, scatophagae likewise could be transmitted to a muscid, This emphasizes the need for a revision of the two species. Low prevalences were recorded of another entom ophthoralean, Furia americana, and of the hyphomycetes Beauveria bassiana a nd Verticillium lecanii. (C) 2001 Academic Press.