Infectivity of two native Egyptian isolates belonging to Heterorhabditis spp. was evaluated against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), compared with imported Steinernema and Heterorhabditis species by two laboratory assays and compatible responses with recommended application concentration (RC) and 0.5 RC of abamectin and fenamiphos. The efficacy of EPNs is directly associated with an increase in concentrations, and percentages of mortalities were higher in the third larvae stage than in the pupal stage. Moreover, native H.bacteriophora (Ar-4 strain) caused the high mortality rates of imported H.bacteriophora (HP88 strain).At concentration 200 IJs/ larvae or pupa, S. feltiae (Filipjev) showed the shortest median lethal time (LT₅₀) for the killing of medfly with LT₅₀ 1.19 days in third-instar larvae and 1.26 days with pupae of C. capitata followed by S. glaseri (NC strain) and S. carpocapase (All strain). On the other hand, native H. bacteriophora (Ht strain) caused the least larvae and pupae mortalities compared to other Egyptian isolates, H. bacteriophora Ar-4 strain with LT₅₀ 2.25 days and 2.38 days in larvae and pupal stage with mentioned concentration, respectively. Regarding the compatibility of abamectin and fenamiphos with EPN species, incompatible responses were revealed with the RC of abamectin. In contrast, an additive effect was exhibited by combining EPN species and 0.5 RC of the tested nematicides. Also, larvae of medfly showed a compatible interaction (additive) when compared with the pupal stage, and H.bacteriophora (Ar-4 strain) was more compatible with two nematicides compared to H.bacteriophora (Ht strain). Current results indicate the feasibility of the integrated management of EPNs with a low dose of chemical pesticides in crop protection.