Mechanisms behind differential white grub host susceptibility to entomopathogenic nematodes

Summary Control of white grubs, the sporadic root-feeding larvae scarabid beetles, is difficult due to their cryptic nature and resistance chemical insecticides. Potential exists for use entomopathogenic nematodes (EPN) such control. The successful infection grubs by EPN, however, limited grubs’ innate reduced susceptibility in form behavioural, morphological physiological defences. This study aimed determine different defence mechanisms against attack EPN. grub species, Pegylis sommeri Schizonycha affinis , which were previously found have a low level Maladera sp. 4, had shown relative high susceptibility, examined. ability EPN penetrate symbiotic bacteria grow inside insect haemolymph, encapsulation rates, as well nematode growth determined. results showed that rates haemolymph varied between species. species able all tested. indicate investigated tended resist initial penetration most studied, thus avoiding infection.