The virulence of entomopathogenic nematode species Steinernema carpocapsae (All) and Heterorhabditis bacteriophora (HP88) was determined against the 3rd instar larvae of Ceratitis capitata (Wied.) throughout three tested media under laboratory conditions. Analysis of data revealed that filter paper media has significant effect than another two media. Such effect descendingly arranged follow: filter paper followed by soil and soil with manure, mortality rates were 40.74, 29.63 and 25.37 respectively. S. carpocapsae (All) was the most virulent than H. bacteriophora (HP88) at all tested media and concentrations. Mortality rates were 78.14, 65.93, 53.33, 39.26 and 21.86% respectively for S. Capocapsae (All) while they were 60.74, 52.22, 37.40, 28.52 and 12.52% respectively, for H. bacteriophora (HP88). Lc50 at 72 hours were obtained for the two entomopathogenic nematode species at the three tested media. Temperature influences nematode virulence, the optimum temperature for nematode pathogenicity was (25oC) then mortality decreased at the lowest (20oC) and highest (30oC) in two tested entomopathogenic nematode species.
Results showed that S. carpocapsae (All) and H.bacteriophora (HP88) caused higher mortality in loamy soil than clay or sandy soil. Mortality rates of medfly larvae were reduced in all soil types mixed with cow manure compared with soil without manure.