Steinernema siamkayai n. sp. (Rhabditida : Steinernematidae), an entomopathogenic nematode from Thailand

Steinernema siamkayai n, sp. (Rhabditida: Steinernematidae) is a new entomo pathogenic nematode isolated in Lohmsak, Thailand. Morphology, hybridisatio n and molecular studies indicated the distinctness of S. siamkayai n. sp. f rom other Steinernema spp. Diagnostic characters include: the total body le ngth (398-495 mu m) and tail length (31-41 mu m) of the third-stage infecti ve juvenile and lateral field pattern with 6-8 longitudinal ridges; the pre sence of a tail mucro in both first and second generation females and males ; the size and shape of the spicules and gubernaculum, and the arrangement of the genital papillae of the first and second generation males; and the s hape of the vulva and tail of the first generation female and second genera tion female.