The white grub, Polyphylla adspersa (Col., Scarabaeidae) is one of the most important Scarabaeid pest of trees in North East of Iran . Long life cycle in three years and cryptic habitat made this pest as a major concern for different control methods. Entomopathogenic nematodes were considered as potential biocontrol agents against such this soil dwelling pest. In this study, a commercial formulation of Heterorhabditis bacteriophora (LARVANEM®) was examined on second and third larval instars and pupae of the white grub collected from urban parks of Mashhad, North East of Iran in 2009. The virulence of H. bacteriophora to larvae was assayed by applying 200 μl of distilled water containing 50, 200, 500 or 1000 IJs onto the soil surface of each cup. Control cups received same amount of water only. Larval mortality was assessed at weekly intervals for 4 weeks. Dead larvae were dissected under the stereomicroscope to confirm that the mortality resulted from nematode infection. The dead larvae were also kept on White traps to observe nematode emergence from nematode-killed insects. Second larvae were significantly more susceptible than third instar to H. bacteriophora. The mean mortality in larval stages was about 42%.Pupal stage of the white grub had high susceptibility to this entomopathogen.When we compared efficacy of other entomopathogenic nematode , Steinernema feltiae and Steinerma carpocapsae , H.bacteriophora had the high efficiency.Larvae of this scarabaeid has evasive behavior with strong grooming.It is concluded that the pathogen, H. bacteriophora, has high potential for using in managing white grubs, P. adspersa .

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