Isolamento e valutazione degli effetti di microrganismi entomopatogeni nei confronti di insetti di interesse agrario, forestale e medico-veterinario

The insecticidal potential of various entomopathogenic bacteria was evaluated by ingestion and/or injection bioassays against noxious insects includingMusca domestica,Ceratitis capitata,Lymantria dispar, andMalacosoma neustria. Bacteria involved in the study included newly isolated soil occurring strains, reference strains (i.e.Bacillus thuringiensis,Brevibacillus laterosporus,Photorhabdus luminescensandXenorhabdus nematophila), and others isolated formGalleria mellonella larvaeinfected with an original collection of entomopathogenic nematods. The new bacterial isolates were identified by phylogenetic analysis involving 16S rRNA gene sequencing.As a result of bioassays, significant differences in the insecticidal potential emerged for diverse bacterial strains and different insect targets.B. thuringiensis,P. luminescinesandX. nematophilawere generally highly toxic against lepidopteran larvae, while differentB. laterosporusstrains showed variable degrees of toxicity against the house fly.Among the others, significant was the pathogenic potential ofBacillus firmus,Paenibacillus tundraeandBacillus psychrodurans, and of new species belonging to the generaSerratia,Pseudomonas,StenotrophomonasandAlcaligenes.These results are discussed in comparison with previous knowledge in the field, highlighting the prospect of a possible use of new bacterial strains for further studies focusing on the development of new actives for the microbial pest management.