Heterodera pratensis sp n., a new cyst nematode of the H-avenae complex (Nematoda : Heteroderidae)

A new cyst-forming nematode belonging to the Heterodera avenae complex and specialized on grass hosts is described as H. prafensis sp. n. The species is widely distributed in grassy habitats in northern Germany and also has b een found in Russia and Estonia. Heferodera pratensis sp. n. is well distin guished from the other species in the H. avenae complex by protein isoelect ric focusing and ribosomal DNA-RFLPs. In its morphological characters it mo st closely resembles H. avenae, H; aucklandica and H. arenaria in the absen ce of an underbridge in the cyst cone. It is distinguished from these speci es by the shape and colour of the cysts, the arrangement of the bullae, and lengths of juvenile body, tail and hyaline part of tail. Diagnostic rDNA-R FLP profiles for H. prafensis sp. n., H. avenae and H. aucklandica are give n.