Isolation and biocontrol efficacy of entomopathogenic nematodes Steinernema carpocapsae, Steinernema monticolum and Rhabditis blumi on lepidopteran pest Spodoptera litura

Abstract

Entomopathogenic nematodes (EPN) are an important component of biological control of agricultural pests. Depending on the ambient temperature, EPNs efficacy may be affected by high temperature between 30 and 40°C is usually featured in tropical and subtropical regions. In the present study, we isolated three EPN strains, namely GNAF1, NBS1 and MAF2, exhibiting high virulence on Spodoptera litura larvae and tested their lepidopteran larval control efficacy at temperatures ranging from 20 °C to 40 °C. Results show that larval control efficacy of the isolated nematodes was not affected at higher temperatures, higher emergence of infective juveniles was observed at higher temperatures, showing that EPN multiplication is not affected at higher temperatures. Based on 18s rDNA sequence these strains were identified as Steinernema carpocapsae -MK350941; Steinernema monticolum -MK503674; Rhabditis blumi -MN453373. The present study shows that these EPN can be used for controlling lepidopteran insect pest in tropical and subtropical agroecosystems.