Photorhabdus and Xenorhabdus as Symbiotic Bacteria for Bio-Control Housefly (Musca domestica L.)

Abstract

Background and Objective: The housefly poses a threat to the public health of humans and domestic animals since it can carry and transmit pathogens. Despite there are many attempts to control this insect, most of them depend on conventional pesticides. Thus, the current study aimed to evaluate the efficacy of whole-cell suspension, cell-free supernatant and crude cells of the symbiotic bacteria Photorhabdus sp. and Xenorhabdu sp., as bio-control agents for housefly stages. Materials and Methods: The Photorhabdus sp. and Xenorhabdu sp., were isolated from the entomopathogenic nematodes, Heterorhabditis indica and Steinernema feltiae, respectively. The phenotypic, as well as the enzymatic characterizations of both bacteria, were determined. In addition, histopathological changes of the alimentary canal of M. domestica adults treated with whole-cell suspensions (at 3×108 cells mLG1) of both bacteria were carefully examined using transmission electron microscopy. Results: The results showed that both symbiotic bacteria significantly suppressed larvae, pupae and adults of M. domestica, particularly when they were applied as whole-cell suspensions. For example, the highest concentration of whole-cell suspension, cell-free supernatant and crude cells of Photorhabdus sp., induced larval mortalities by 94.7, 64.0 and 45.3%, while those of Xenorhabdus sp., induced larval mortalities by 58.7, 46.7 and 30.7% at 96 hrs, respectively. The results also showed that whole-cell suspensions of both symbiotic bacteria caused severe histopathological changes in the ultrastructure of the treated adults’ alimentary canal. Conclusion: Both symbiotic bacteria can be effectively used, particularly the whole-cell suspension, as bio-control agents against the housefly either in the larval or adult stage.