The genus Pratylenchus Filipjev, 1936 includes at present about 100 described species. All are known as plant-parasitic on many plant roots, rhizomes and tubers. With their mobile endoparasitic behaviour they induce typical discolored patches or lesions on roots and are therefore included in the so called lession nematodes. Pratylenchus crenatus was described by Dr. P.A.A. Loof in 1960 from the Netherlands. Nowadays this asexual species (males are rare) is known from the Northern temperate zone (North America, Europe and Japan), but also found in South Africa and Venezuela. It is particularly damaging on grasses and cereals.