Assessment of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) Against Ceratitis capitata Wiedemann

Abstract

The Mediterranean fruit fly (Medfly), Ceratitis capitata Wiedemann is the most cosmopolitan and invasive among all species in the family Tephritidae. Concerns related to insecticides misuse create an opportunity for the development and use of biocontrol agents such as the entomopathogenic nematodes (EPNs). Virulence assays performed using several native isolates of EPNs against 3rd instar larvae (L3) of C. capitata showed no significant differences between H. bacteriophora SR1 MK474617.1 and. H. bacteriophora MG2 MK474643.1. The highest mean mortality value reached by H. bacteriophora GA1 MK474645.1 was 69.19%. An experiment carried out under semi-field conditions to evaluate the effect of H. bacteriophora GA1(MK474645.1) isolate on the 3rd instar larvae of medfly showed that inoculation with different concentrations of infective juvenile (IJ) (600, 300, 150 IJ/cm2 ) caused the highest larval mortality rate (66.89%) at 600 IJ/cm2 , with a LC50 value of 88 IJ/cm2 in soil. Statistical analysis of the effect of H. bacteriophora on mortality exhibited significant differences (p≤0.05) when applied at concentrations of 600 IJs and 150 IJs. These findings suggest that application of EPNs could be an effective option to suppress C. capitata populations and it can be included as an effective component in integrated pest management (IPM) programmes against Medfly. Keywords: Biological control, Ceratitis capitata, Heterorhabditis bacteriophora, Citrus Lattakia, Syria.