Taxonomic analysis of soil phytopathogenic mycocomplexes of different varieties of faba beans in the Central Black Earth Region of the Russian Federation

The species composition and structure of soil complexes of micromycetes under faba beans were studied. The indices of the frequency of occurrence and abundance of microscopic fungi species in soils under ten varieties of faba beans were analyzed in comparison with the control soil (pure fallow). The control revealed 20 species of micromycetes from 10 genera. The species from 16 genera were identified under the varieties of beans in the soils. Most micromycetes belong to the Ascomycota division (classes Dothideomycetes, Eurotiomycetes, Saccharomycetes, and Sordariomycetes). In the soil of faba beans, the number of micromycete propagules is significantly higher (30.6 ± 2.5 thousand CFU / g soil) than in the control (12.5 ± 2.3 thousand CFU / g). The biodiversity of micromycete complexes in the control soil was maximal (Pielu index 0.75). An increase in the dominance index under the studied varieties of beans (Simpson’s index 0.09-0.24) was noted in comparison with the control soil, with a dominance index of 0.07. Phytopathogenic species of micromycetes were found: fungi Ascochyta fabaе, Alternaria tenuissima, Cladosporium herbarum, Fusarium culmorum, F. oxysporum, F. solani, and Ulocladium botrytis