The Effect of some Insecticides on Two Entomopathogenic Nematodes and Evaluation of Its Virulence on the Greater Wax Moth Galleria mellonella

Abstract

The toxicity effect of five insecticides (Dipel 2x, Radiant, Proclaim, Aphox and Coragen) on two species of entomopathogenic nematodes (EPNs) (Heterorhabditis bacteriophora BA1 and Steinernema carpocapsae BA2), were evaluated under laboratory conditions at different concentrations 100%, 50% and 25% of field rates (FR). Moreover, the virulence of insecticide-treated EPNs against the l st nymphal instar of the greater wax moth Galleria mellonella L. (Lepidoptera: Pyralidae) was also evaluated. Data indicated that all insecticides showed negative effect on the tested infective juveniles (IJs) of EPNs and the percentages of mortality were in order of H. bacteriophora BA1>S. carpocapsae BA2 and were concentration-dependent; significant differences existed between untreated (control) and insecticide treatments EPNs. Proclaim insecticide recorded the highest mortality rate in EPNs at all tested concentrations 24, 48 and 72 hours post treatment. Regarding the effect of tested insecticides on the virulence and the reproductive capacity of treated EPNs, data indicated that the ability of insecticide-treated EPNs to locate and infect larvae of G. mellonella decreased after exposure to insecticide and consequently reproductive capacity of EPNs was significantly reduced.