PATHOGENICITY, PROGENY PRODUCTION AND HISTOPATHOLOGICAL EFFECTS OF THREE ENTOMOPATHOGENIC NEMATODES IN THE GREATER WAX MOTH, GALLERIA MELLONELLA (L.)

Entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis are associated with bacterial symbionts of the genus Xenorhabdus and Photorhabdus, respectively. They are being produced commercially and used as biological control agents against many soil insect pests. The present study was carried out to investigate the effectiveness of entomopathogenic nematode species "Heterorhabditis bacteriophora, Steinernema carpocapsae and Steinernema riobravis" against the full-grown larvae of greater wax moth "Galleria mellonella". It was found that the mortality percentage increased as the concentration of the infective juveniles (IJs) increased. Generally, H. bacteriophora was more effective than S. carpocapsae and S. riobravis. The production rate increased as the concentration of IJs increased. H. bacteriophora was the highest reproductive strain than S. carpocapsae and S. riobravis at the five tested concentrations. The three nematode species affected the muscles and fat tissues, where muscle fibers suffered destruction with some fragmentation, also complete destruction and disintegration of tissues was noticed in the treated G. mellonella larvae.