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

Steinernema siamkayai n. sp. (Rhabditida: Steinernematidae) is a new entomopathogenic nematode isolated in Lohmsak, Thailand. Morphology, hybridisation and molecular studies indicated the distinctness of S. siamkayai n. sp. from other Steinernema spp. Diagnostic characters include: the total body length (398-495 μm) and tail length (31-41 μm) of the third-stage infective juvenile and lateral field pattern with 6-8 longitudinal ridges; the presence 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 shape of the vulva and tail of the first generation female and second generation female.