Efficacy of commercial strains of Bacillus thuringiensisin controlling Tuta absoluta: laboratory tests

Abstract: Several commercially available strains of the entomopathogenic bacteria Bacillusthuringiensis (Bt) were tested to evaluate their efficacy in controlling Tuta absoluta, in terms oflarval mortality, of reduction in larval feeding activity and subsequent damage. Tests wereconducted on T. absoluta young larvae under laboratory and extended laboratory conditions, bothafter ingestion and topical application. The mortality rate, the number of infested leaflets and theamount of infested surface per each leaflet were recorded. The formulation containing the strainkurstaki SA12 resulted the most effective in controlling T. absoluta in terms of induced mortalityas well as damage reduction, both in the topical and ingestion toxicity trial. Similar trend,although without significant differences, was recorded in the extended laboratory trial.