Effects of Some Insecticides and Nematicides on Penetration, Infectivity and Reproduction of the Entomopathogenic Nematodes

Abstract

Laboratory bioassays were conducted to determine the effects of seven insecticides and three nematicides on penetration , infectivity and reproduction of the infective juveniles (IJs)of entomopathogenic nematodes Heterorhabditis bacteriophora and H. indica nematode species. In penetration assay, results of tested seven insecticides i.e. abamactin, Bacillus thuringiensis B.t. as bioinsecticides, chloropyrifos, chloropyrifos-methyl, esfenvalerate, methomyl and profenfos as chemical insecticides on both of entomopathogenic nematodes, indicate that the more pesticides events for reduction in average numbers of IJs nematodes penetrating last instar larvae of Spodoptera littoralis was chloropyrifos-methyl and methomyl at 100% reduction comparing with control. While the more pesticides compatible with tested nematode species are abamactin and B.t on the three tested rates of application. In infectivity and reproduction assays, three nematicides has been tested i.e. aldicarb , ethoprophos and cadusafos at three rates of application after four periods of exposure soil to tested nematicides at one day, one week, two weeks, three weeks. Results show that, the most compatible nematicides with H. bacteriophora are cadusafos in both assayes production and efficiency against Galleria mellonella larvae comparing with control, while other pesticides tested is not compatible with this nematode where the aldicarb at percentage 100% reduction in events insect larvae death, as well as test production by day, week, 2 weeks. Overall, results indicate the feasibility of an integrated use of these nematode species and chemical pesticides in crop protection.