Efficacy of some geographical isolates of entomopathogenic nematodes against Leptinotarsa decemlineata (Say) (Col.: Chrysomelidae)

Abstract : Entomopathogenic nematodes (EPNs) are used to control several agriculturally important insect pests of the different orders. In this study the ability of four geographical isolate of Heterorhabditis bacteriophora and three species of Steinernema include S. bicornutum, S. carpocapsae and S. feltiae were investigated for control of Colorado potato beetle in laboratory conditions at 25±2 ºC and photoperiod of 12:12 (L:D). The efficacy of EPNs was tested at five concentrations including 100, 200, 400, 500 and 1000 infective juvenile (IJs) per individual with three methods, filter paper assay, leaf assay and soil assay at four exposure times. In filter paper assay and leaf assay methods, H. bacteriophora IRA10 had the highest toxicity and S. bicornutum IRA7 was the lowest one. There are no significant differences between strains at lowest concentration in all exposure times. In soil assay method, H. bacteriophora IRA12 had the highest mortality percentage and S. bicornutum IRA7 was the lowest one. Our study clearly shows that both species and geographical isolates of same species of etomopathogenic nematodes may have significantly different virulence against specific pest target. Nevertheless these results it is difficult to predict which species/isolate might be the most effective biological control agent for suppression of L. decemlineata in field conditions but at least we can expect that the most effective EPN among studied isolates might be H. bacteriophora IRA10
Keyword : Entomopathogenic nematods, geographical isolates, Heterorhabditis, Steinernema, Leptinotarsa decemlineata
Author(s) : , N. E. Kary, H. Rafiee-Dastjerdi, D. Mohammadi, S. Afghahi
Downloads : 1173


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