The insecticidal activity of an entomopathogenic nematode Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus luminescens against Periplaneta and Blattella cockroaches

japonica, however, did not differ from that of the control at all of the tested concentrations; whereas, the mortality of B. germanica was relatively higher than that of Periplaneta cockroaches. Second, we tested the pathogenicity of P. luminescens alone against the three Periplaneta species by injection of bacterial cells. All tested cockroaches were found to be killed within 2 – 4 days. These results would suggest that Periplaneta are susceptible to P. luminescens ; however, in the bait experiment , H. bacteriophora was unable to effectively establish a lethal infection of P. luminescens . Our results indicate that susceptibility to EPN infection and bacterial pathogenicity should be evaluated separately, and that much less H. bacteriophora is required to kill B. germanica than is needed to kill three Periplaneta cockroaches. Nematol. Res. 50 ( 2 ), 27 – 33 . ( 2020 )