In present investigation Steinernema sp. isolate CS1 was identified with the aid of numerical taxonomy as an
additional tool. Presence of two horn-like structures on head region of 3rd stage infective juveniles (IJs) placed the
nematode in bicornutum group and differentiated from other compared Steinernema spp. The morphological
characters of 3rd stage infective juveniles and 1st generation males showed close resemblance with S. abbasi, S.
thermophilum and S. pakistanense however, the body length was varied (583mm vs 541mm, 555 mm and 683 mm,
respectively). The morphometrical characters and life history events placed the present specimen near to the S.
abbasi. Results obtained through the phylogenetic utility of maximum parsimony, maximum likelihood and
neighbour joining methods and comparative account on nucleotides analyses based on ITSs study confirmed the
present specimens as isolates of S. abbasi. The nucleotide composition resemblance within 5.8S gene with other
Steinernema species evident the less polymorphism and highly conserved nature of this region as compared to ITS1
and ITS2 and delimit the relationship of steinernematid nematodes.