Determination of Entomopathogenic Nematode Fauna in Şırnak, Türkiye

Abstract

With increasing concerns over the adverse environmental impacts of chemical pesticides, there has been a growing interest towards sustainable pest management strategies worldwide. In this context, entomopathogenic nematodes (EPNs) have emerged as promising biological control agents against insect pests in agricultural production. This study focused on the isolation, identification, and characterization of entomopathogenic nematodes (EPNs) in Şırnak Province, Türkiye. Over the period from July to September 2023, a comprehensive survey involving the collection of 256 soil samples led to the successful isolation, of 11 EPN isolates, which accounted for 4.3% of the samples. Morphological examinations and molecular diagnostics, including mitochondrial COI and 18S rDNA gene regions, facilitated the precise identification of these isolates. Notably, our findings revealed a diverse population of EPNs, predominantly Heterorhabditis bacteriophora, comprising five isolates, alongside four distinct species of Steinernema (one Steinernema carpocapsae, one Steinernema affine, two Steinernema feltiae and two Steinernema sp.). Phylogenetic analysis, utilizing the mitochondrial cytochrome oxidase subunit I (COXI) and the 18S rDNA gene regions, indicated low genetic variability within H. bacteriophora, whereas a higher level of diversity was observed among Steinernema species. Notably, the presence of diverse EPN species highlights their capacity as effective biocontrol agents against a range of insect pests. These findings provide valuable insights into the biodiversity of EPNs in Şırnak Province and underscore the significance of utilizing local isolates for sustainable agricultural practices. Further research is warranted to elucidate the efficacy of these isolates in integrated pest management strategies tailored to the region's specific agroecological conditions.