Species of Two Genus Geocenamus and Merlinius of Rapeseed Fields in North Khorasan Province

In order to identify the plant parasitic nematodes of rapeseed fields in North Khorasan province، during 2007-2008، 40 soils and root samples were collected. Nematodes were extracted by centrifugal flotation technique and transferred to glycerine according to the modified De Grisse method (1969). The permanent slides were prepared from the extracted nematodes. The nematodes were identified by light microscopy based on morphological and morphometrical characters. In this study، from genus Geocenamus، three species G. quadrifer، G. tessellates، G. rugosus and genus Merlinius four species M. brevidens، M. microdorus، M. nanus، and M. nothus were identified. G. tessellates، is reported for the first time from Iran.