Bioecological features of pathogenic mycobiota formation in flower and decorative plants (on the example of Callistephus chinensis (L.) Nees) urban ecosystems greenization

Abstract

The phytopathological condition of Chinese calisthephus groups in urbanized ecosystems of the forest-steppe zone was assessed and the species composition of pathogenic mycobiota was established as the main natural causes of violations of the complex green zone and compositional integrity of flower crops phyto-cenoses. The species composition was specified and a taxonomic assessment of the pathocomplex was carried out, where the kingdom of Fungi occupies a dominant place and is represented by 20 (84 %) species of pathogens from 11 (85 %) genera, 9 (82 %) families, 7 (78 %) orders, 2 (67 %) divisions, where Ascomycota has an advantage, which is represented by 18 (90 %) species, and the number of species is dominated by the orders Dothideales (6 species, 26 %) and Hypocreales (5 species, 21.7 %). Ecological niches of the main pathogens of Chinese calisthephus were established: micromycetes Botryotinia fuckeliana (de Bary) Whetzel., Fusarium oxysporum Schltdl. (1824), Verticillium albo-atrum Reinke & Berthold. V.dahliae Kleb. detected on all vegetative and reproductive organs; Phytophthora cactorum J. Schröt. (1886) – underground and aboveground; Rhizoctonia solani J.G. Kühn (1858) – underground parts and seeds, Alternaria zinniae M.B. Ellis (1972) – aboveground parts and seeds. In the phytopathogenic complex of underground organs the dominant place is fusarium root rot caused by Fusarium oxysporum, F.culmorum (Wm.G. Sm.) Sacc. (1895), Gibberella zeae (Schwein.) Petch, G. avenacea R.J. Cooke, Haematonectria haematococca (Berk. & Broome) Samuels & Rossman with average annual prevalence ranging from 5 to 89 %. The average annual prevalence of fusarium wilt of Chinese calistefus caused by Fusarium oxysporum, F. oxysporum f. callistephi W.C. Snyder & H.N. Hansen was 40.9 %. Pathogenic mycobiota according to the indicators of infection transmission factor belongs to the following ecological groups: airborne infection (54.2 %), soil infection (45.8 %); according to ecological and trophic properties they can be classified as biotrophs (70.8 %) and saprotrophs (29.2 %). Key words: urban ecosystem, flower-ornamental plants, mycobiota, phytopathogenic complex, Callistephus chinensis (L.) Nees, Fusarium oxysporum Schlecht., Ecological groups.