Three species of entomopathogenic nematodes of the family Steinernematidae (Nematoda: Rhabditida) new to continental Portugal

Abstract

Abstract In order to determine the species of entomopathogenic nematodes in Continental Portugal, a survey was conducted in the country. Nematodes were recovered from soil samples collected from Alentejo, Algarve, center and the north of Portugal from 2006-2009. Isolates were identified based on morphology and sequence analysis. Phylogenetic analysis was based on sequences of partial 28S (D2D3), internal transcribed spacer (ITS) and cytochrome oxidase c subunit I gene (COX I). Isolates 59F, 15G, 20F and 2B were characterized in detail. Isolate 2B shows a morphology identical to Steinernema intermedium which is a member of the affine/intermedium-group and is characterized by the presence of strongly curved and robust spicules with a distinct rostrum, in the male, and dorsal tail depression in third-stage infective junveniles (IJ). However, the phylogenies based on the three molecular markers revealed that isolate 2B is more closely related to S. affine than with S. intermedium. The morphological results for isolate 20F identify it as S. kraussei which is a member of kraussei/feltiae–group, characterized by IJs with a straight body of medium length (mean = 700–950 μm), lateral field mostly with eight ridges, rather broad, flatly rounded and continuous cephalic region, excretory pore at level of mid-pharynx; males with mucronate tail, yellowish spicules ca. 50 μm long and wide manubria; females with short conoid tail with pointed non-mucronate tip. Based on morphology and sequence analysis, isolates 59F and 15G were considered conspecific and identified as a species belonging to the glaseri–group. More detailed studies are necessary to solve if these isolates represent a new species.