Distribution of Fungi from the Genus <Emphasis Type="Italic">Fusarium</Emphasis> Link. on Cereals

The species composition of fungi from the genus Fusarium was studied, and the frequency of occurrence on cereals was determined. Populations of Fusarium spp. were represented by widespread species F. culmorum, F. heterosporum, F. sporotrichioides, F. oxysporum, F. nivale, F. graminearum, F. avenacеum, F. gibbosum, F. sambucinum, F. moniliforme, etc. The dynamics and frequency of occurrence of Fusarium spp. has made it possible to characterize the state of the species of fungi in a wide range of climatic areas of cereal cultivation in the Russian regions. The prevalence of the genus Fusarium was caused by the cultivars’ susceptibility to micromycetes. The frequency of occurrence of Fusarium species isolated from roots was steady, and, on the ears, it depended on the influence of weather conditions during the growing season of plants. The study of the intraspecific variability of fungi from the genus Fusarium has revealed a significant difference in signs of toxicity and pathogenicity depending on biotic and abiotic factors. More than 50% of strains from the genus Fusarium possessed low pathogenicity but had severe toxicity to wheat seedlings. Most strains of F. sporotrichiodes, F. culmorum, and F. sambucinum were highly pathogenic (from 36.4 to 55.6%) and toxic (from 55.6 to 81.3%). High adaptability to preservation in the soil and on the roots of weeds and crop residues of most crops expressing pathogenic and toxic activity was conductive to the widespread Fusarium spp.