Isolation, identification, and pathogenicity of entomopathogenic nematodes occurring in Cappadocia Region, Central Turkey

A survey for naturally occurring entomopathogenic nematodes (EPNs) was conducted in various agricultural fields in central Turkey, Nevsehir, between 2015 and 2016 years. EPNs were recovered from 20 of 112 soil samples (17.9%). Seventeen isolates were identified as Steinernema feltiae (Rhabditida: Steinernematidae). One was unknown Steinernema sp. (Rhabditida: Steinernematidae), and two were Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae). The most common species was S. feltiae, which was recovered from 5 out of 8 sites. The pathogenicity of these isolates was evaluated on the last larval instar of Galleria mellonella L. (Lepidoptera: Pyralidae) at different concentrations (25, 50, 100 IJs) in the laboratory at 25 ± 1 °C. Maximum mortality rate (87%) was achieved from the H. bacteriophora AVB-15 isolate at the lowest concentration after 48 h post-inoculation, while the only isolate that caused maximum mortality of (100%) at the concentration of 50 IJs/ml, 24 h post-inoculation was S. feltiae DDKB-17 isolate. All isolates showed high pathogenicity on G. mellonella last instar ranging from 63 to 100% at the concentration of 100 IJs/ml, 48 h post-inoculation. The present survey revealed that these EPNs are commonly present at Nevsehir, and they might have a good potential in biological control of insect pests.