Researches on entomopathogenic bacteria and applications for fly pest control in a Mediterranean region (Sardinia, Italy)

During the last few years, investigations were carried out in Sardinia (Italy) to isolate naturally-occurring soil bacteria and detect their toxicity against medfly (Ceratitis capitata), olive fruit fly (Bactrocera olea) and housefly (Musca domestica) as well as some of their pupal parasitoids. Strains of Bacillus thuringiensis were isolated and then comparatively studied with strains of other geographic origin. Morphological (presence of parasporal inclusions) and genetic (16S rRNA gene sequence, detection of cry genes) observations and protein profile analysis by SDS-PAGE were used for identification and characterization of the Bacillus thuringiensis isolates. Among about 300 different bacterial isolates, 4 were significantly toxic to housefly adults, 1 to housefly larvae, 11 to adult of olive fruit fly, 20 to olive fruit fly larvae, 4 to adult of medfly, and 22 to medfly larvae. No significant toxicity was detected against the Hymenoptera Opius concolor and Muscidifurax raptor (olive fruit fly and housefly pupal parasidoids, respectively). Experimental treatments in olive crops against olive fruit fly adults and in livestock against both housefly adults and larvae were carried out with formulations of the most toxic bacterial strains, encouraging the introduction of microbiological control in the integrated pest management of these fly species.