Heterodera betae sp n., the yellow beet cyst nematode (Nematoda : Heteroderidae)

The yellow beet cyst nematode Heterodera betae sp. n. is described from gla sshouse populations originally obtained from a sugar beet field near Karken , Germany and maintained on sugar beet (Beta vulgaris) in Munster and Elsdo rf, Germany. The new species resembles species of the Heterodera trifolii c omplex in the general morphology of the cyst and the shape of the fenestrat ion of the vulval cone. The new species differs from all those species, exc ept H. rosii Duggan & Brennan, 1966, by its longer body and stylet and the more robust stylet knobs of the infective juveniles. It differs from H. ros ii in that it infects sugar beet, and has no males. Heterodera betae can be distinguished from its close relative H. trifolii Goffart, 1932, by RFLPs of the ITS regions of the rDNA obtained after amplification with the primer s F194 and F195, and digestion with the enzymes ScrFI, MvaI and PvuII.