STEINERNEMA CERATOPHORUM N-SP (NEMATODA, STEINERNEMATIDAE), A NEW ENTOMOPATHOGENIC NEMATODE FROM NORTHEAST CHINA

Steinernema ceratophorum n. sp. was isolated from soil in Liaoning and Jining Provinces of China. Morphological, cross-breeding and DNA stud ies support the distinctiveness of S. ceratophorum n. sp. in compariso n with four morphologically similar Steinernema species: S. affine, S. intermedium, S. ribobrave and S. bicornutum. Diagnostic characters in clude: body length of infective juvenile, juvenile lip region with two horn-like structures and lateral field with six or eight longitudinal ridges; tail tip of first and second generation males lacking mucron; spicules of first generation male curved, dark yellow in colour and 7 1 mu m long; tail tip of first generation female with small mucronate projection; and second generation female with fine mucronate process a bout 5.5 mu m long. In addition, the restriction fragment length patte rn (RFLP) of the ITS region of the ribosomal DNA repeat unit is differ ent from other Steinernema spp., and S. ceratophorum n. sp. did not hy bridise with S. riobrave, the species with the most similar RFLP.