Invasion of <i>Popillia japonica</i> in Lombardy, Italy: Interactions with soil entomopathogenic nematodes and native grubs

The recent invasion of the Japanese beetle Popillia japonica Newman (Coleoptera: Scarabaeidae) in northern Italy offered opportunity to explore entomopathogenic nematodes (EPNs) associated with soil hay meadows. A total 61 sites were considered for nematode sampling, and from 17 them (27.9%) EPNs isolated further characterized molecular morphological techniques as well laboratory bioassays. Two main species, Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) Steinernema carpocapsae Weiser Steinernematidae) recorded same frequency together a few other species Oscheius sp. Phasmarhabditis sp.). newly EPN populations their activity (penetration rate) infectivity P. grubs. occurrence was related time at each sampling site there evidence density-dependent response community density. apparently did not significantly affect native grubs, although tendency decline observed should be investigated.