First report of the entomopathogenic nematode, Steinernema carpocapsae, from Moghan region of Iran and its efficacy against the turnip moth, Agrotis segetum Denis and Schiffermuller (Lepidoptera: Noctuidae), larvae

Abstract

During a survey of entomopathogenic nematodes (EPNs) in Moghan region of Iran in 2015, a steinernematid species was isolated, using the Galleria-baiting method. Based on its morphological and phylogenetic analysis of molecular data, the isolate was identified as Steinernema carpocapsae. The ITS rDNA sequence was deposited in NCBI (National Center for Biotechnology Information) with accession number of MF187616.1. Nucleotide row data was edited, using MEGA 6.0 software, and homologous sequences were involved in analysis, using Blast software. Sequences were aligned using Clustal W. Bootstrap analysis. The phylogenetic tree was constructed by the maximum likelihood method, using MEGA 6.0 software, and Steinernema feltiae was used as out-group. The turnip moth, Agrotis segetum Denis and Schiffermuller (Lepidoptera: Noctuidae), is one of the most important and destructive cutworm pests in Moghan. Therefore, the lethal effect of S. carpocapsae isolate Moghan (IRMoghan) was evaluated in a soil assay against the last instar larvae of A. segetum under laboratory conditions. The bioassay results showed high susceptibility of the larvae to S. carpocapsae. The LC10, LC50, and LC90 values were 9.9, 54.13, and 246.2 IJs (infective juveniles) per larva of the pest, respectively (χ2 = 7.36; df = 3, P value = 0.061). Reproduction of the EPNs within the dissected cadavers was observed. The bioassay results indicated that the new isolate is a promising biocontrol agent against A. segetum larvae with success recycling through them.