Researching the special and infraspecial structure in causative agent populations of the most dangerous diseases root rots of cereals in various regions of the Russjan Federation has been carried out. The defeat of cereals root rots old in Russia causes in the a complex patogenic. More often meet Fusarium culmorum (W.G.Sm.) Sacc., F. oxysporum (Schlecht.) Snyd.et Hans., F. heterosporum Nees., F. sporotrichiella nom.nov. Bilai F. gibbosum App.et Wr.emend Bilai., F. avenaceum (Fr.) Sacc. and Bipolaris sorokiniana (Sacc.) Shoem., Alternaria spp.