Natural abundance and host plant preference of the endoparasitoids O. pallipes was studied in Ojelat region. Four host plants were studied [tomatoes (Solanum lycopersicum) pepper (Capsicum annuum) eggplant (Solanum melongena) and kidney bean (Phaseolus vulgaris)] The parasitoids showed high populations in April and May that kept the populations of the serpentine leafminer L. trifolii at low densities till the end of the season on all studied host plants. O. pallipes recorded two peaks of abundance on the four studied host plants recording (19, and 24 individuals/ 50 infested leaflets) on tomatoes, (18, and 16 individuals/ 50 infested leaflets) on pepper, (26 and 20 individuals/ 50 infested leaflets) on eggplant and (32, 26 individuals/ 50 infested leaflets) on kidney bean during the season of the study. O. pallipes showed a relatively low preference towards kidney bean and eggplant compared with pepper and tomatoes.