New Distributional Record ofSteinernema hermaphroditum(Rhabditida: Steinernematidae) from Kerala, India

A total of 141 soil samples were collected from coconut gardens in various tracts of Alappuzha, Kollam, Pathanamthitta, Idukki and Eranakulam districts of Kerala for the natural occurrence of EPN using soil-baiting techniques with greater wax moth larvae, Galleria mellonella. Among these samples, 13.5% were found positive for EPN, which included three steinernematids and 16 heterorhabditids identified based on the characteristic colour of the infected cadavers. Three heterorhabditids and two steinernematid isolates were further subjected to molecular characterization by sequencing ITS region of the ribosomal DNA using 18s and 26s primers. All the three heterorhabditid species intercepted in the survey, were found to have 99% sequence similarity with Heterorhabditis indica. Both the steinernematid isolates were found to be belonging to the glaseri group. The steinernematid isolate CPCRI0804 was found non-homologous with any of the described species and, therefore, presumed to be a new species for identification. The presence of long and highly curved spicule is the striking feature of this unidentified species. One of the steinernematids (CPCRI0905) was 99% homologous with Steinernema hermaphroditum and is the first report of this species from South India. The identity of this isolate was confirmed based on the morphological and morphometric characters as well as the presence of first generation hermaphroditic females, which is a unique characteristic feature of S. hermaphroditum.