Features of the Structural and Functional Organization of Pathogenic Fungi Herbage of Silvopastoral System

Abstract

The materials devoted to the study of the features of the organization of the microflora communities of the pathogenic microflora of grassy vegetation of pastures of the open steppe and under the protection of artificial plantations are presented. The facilities are located on the lands of the North-Caucasus branch of the Federal Science Center for Agroecology, Russian Academy of Sciences in the Stavropol Territory. The identification of the species diversity of phytopathogens and the assessment of the intensity of plant infection were carried out by visual examination of the vegetation and subsequent analysis of the samples in the laboratory using methods generally accepted in phytopathology. The assessment of the biocenotic role of protective forest stands and the peculiarities of the formation of biotic microflora complexes was carried out using indices that are widely used to characterize biological diversity. The climate here is sharply continental, dry, with increased wind activity during the spring and autumn-winter periods. A distinctive feature is the frequent recurrence of southerly and southeastern winds. Soils are light brown, partially saline. Found 139 plant species. The species composition of pathogenic microflora, parasitic on plants of pasture grass stand, which is represented by 116 species, is described. Dominant species parasitizing on grassy vegetation of forest pastures have been established. Of the pathogens, mushrooms from the Pucciniomycetes and Dothideomycetes classes predominate. Most often on grassy vegetation of pastures there are powdery mildew fungi of the genus Erysiphe (11 species), parasitic on widespread cereals, the genus Leveillula (5 species), found on Asteraceae and Labiatae, as well as species of fungi of the genus Ustilago (7 species). Rust fungi of the genus Puccinia are widely represented in these biotopes - 39 species. Especially harmful pathogens annually cause significant damage to plants, are economically significant, and in favorable weather conditions, they cause epiphytotics: Erysiphe umbelliferarum f. falcariae, E. graminis f. agropyri, E. graminis f. bromi, Uromyces glycyrrhizae, Ustilago bromivora etc. An assessment of the α-diversity of the parasitic mycobiota revealed that the mycocomplex of the grass stand under the protection of shelterbelts with Elaeagnus angustifolia and Robinia pseudoacacia is characterized by the highest species abundance.