Institut, pgt Bol’shie Vyazemy, Odintsovo Region, Moscow Province, 143050 Russia, e-mail kiseleva@vniif.ru; Mordovia, 430005 Russia, e-mail van20099@mail.ru A b s t r a c t The root rot caused by fungi of L.) and barley ( and ter and spring cereals. <...> The specific rang of the disease agents is characteristic to certain ecological and geographical areas. <...> The soil is the basic source of the infection. <...> Pathogenic properties of the root rot agents is due to their ability to develop hydrolytic enzymes and toxins, such as helminthosporol, helminthosporal, victoxin in zearalenone, diacetoxyscirpenol, nivalenol in spp., etc. <...> In the paper the study of fungal species causing root rot and leaf spot of cereals in the Republic Mordovia territory, and also pathogenic properties of widespread and infrequent spp. has been represented. <...> Damaged plants of spring wheat, barley and oats (a total of 38 cultivars) in heading stage were sampled. <...> The infected leaves and roots were cut into fragments, aseptically sterilized and placed in Petri dishes on 2 % potato-glucose agar. <...> During growth, the mycelia slices were transferred on a new nutrient medium. <...> As a result, the pure cultures were isolated and the morphology of their colonies were studied. <...> For the evaluation of morphology uniformity of strains, we isolated not less than 20 single spore cultures of fungi using serial cultivations of spore suspensions. <...> Pathogenic and toxic properties of spp. and ( , , ) prevailed on roots of wheat, barley and oat plants. <...> Isolates of var. f. , spp. and , ) and , 68, Bol’shevitskaya ul., Saransk, Republic of sp. strains were studied in biotest on seeds of susceptible wheat cultivar Mironovskaya 808. <...> Finally, there were a total of 457 isolates of pathogenic and saprophytic fungi. <...> No clear specialization of fungi species to cereals was shown. <...> There were many accompanying saprophytic isolates allocated together , , , etc. <...> The wide rang of plant-hosts was found out for , sp. with stable morphology , The widespread species of fungi had various pathogenic and toxic properties, indicating their strong intraspecific variability. <...> Rare fungal species possessed toxicity to test-plant seedlings, but were not pathogenic. <...> This fact possibly explains their low frequency <...>