The infectivity two steinernematid of entomopathogenic nema­todes species, namely Steinemema carpocapsae All and Steinernema ri­obravae (Weiser 1955) Poinar1995 and two native isolates of Hetero­rhabditis bacteriophora Poinar 1975 (AS1 and Eg-1) to prepupae and pupae of peach fruit fly, Bactrocera zonata(Saunders)(Diptera Tephriti­dae )was evaluated . The data obtained indecated that , Bactrocera zon­ate prepupae are very susceptible to nematode infection, low differents between pupae and prepupae ,the mortality ranged between 16.67 to 93.70% and 28.72 to 91.49%, respectivaly.The two strains belonging to genus Heterorhabditis which seem to be infective to the pupal stage than those belonging to genus Steinernema. The opposite was true in case of the prepupal stage, where steinemematid species were more in­fective than heterorhabditid strains.