Susceptibility of Ceratitis Capitata (Wied) Larvae and Pupae to Entomopathogenic Nematodes, Steinernema Carpocapsae, ond Heterorhabditis Bacteriophora

Abstract

The pathogenicity of the entomopathogenic nematodes, Steinernema carpocapsae and Heterorhabditis bacteriophora to larvae, and pupae of the Mediterranean fruit fly, Ceratitis capitata (Wied.) was investigated. The activity of IJs was correlated with EPNs species as well as concentration rate.    S. carpocapsae caused the highest mortality rates of larvae at all concentrations in filter paper and soil assays. In filter paper assay; S. carpocapsae  at the concentrations of 50,100 and 200 IJs/cm2,  caused mortality rates of 68.7, 79.3, and 85.2% respectively,  while the H. bacteriophora caused 53.6, 61.8, and 72.3%, respectively, at the same concentrations. The LC50 values were 21.77 IJs/cm2 for S. carpocapsae, and 42.96 IJs/cm2 for H. bacteriophora,. In soil assay; the differences between the two species were not significant, with the persistence of the probability of the S. carpocapsae, which was confirmed by the LC50 value (25.58 IJs/ cm2for S. carpocapsae and 81.42 IJs/ cm2for H. bacteriophora).   EPN species were less efficient in infecting pupae,. In filter paper assay; H. bacteriophora caused the higher mortality rates at all concentrations without significant differences (48.37, 52.3, and 58.6%) respectively, while they were 34.6, 38.3, and 53.27 % for S. carpocapsae . The LC50 for S. carpocapsae was 184.8 IJs/ cm2, while it was 55.57 IJs/ cm2 for H. bacteriophora.  Treating of the pupae in soil gave   31.37, 42.3, and 45.6% mortality  for H. bacteriophora and 24.6, 28.27, and 36.27% for S. carpocapsae at the mentioned concentrations respectively.