IDENTIFICATION OF MYCOBIOTA AND DIAGNOSIS OF SOYBEAN SEED DISEASES

Micromycetes that colonise soybean seeds reduce their sowing quality, causing loss of germination, rotting and death of seedlings, and the appearance of diseases on young plants. Infection-free seed is one of the factors that ensure crop growth. Therefore, the study of mycobiota of seeds is relevant for the implementation of preventive disease control measures. The purpose of this study was to identify phytopathogenic fungi that colonise soybean seeds and to establish their species composition. The seed samples were selected in the conditions of the Ukrainian Scientific Plant Quarantine Research Station (Chernivtsi Oblast) of the Institute of Plant Protection of the National Academy of Agrarian Sciences during 2019-2021. Mycological studies of soybean seeds were performed in the scientific laboratory of the Department of Phytopathology of the National University of Life and Environmental Sciences of Ukraine using the biological method from subsequent morphological and microscopic analysis of pathogens. It was established that the species composition of mycobiota of soybean seeds is diverse and is represented by 17 species: Reronospora manshurica (Naum.) Syd. (downy mildew pathogen), Sclerotinia sclerotiorum de Bary (white mold pathogen), Botryotinia fuckeliana Whetzel. (grey mold pathogen), Diaporthe sp. (Phomopsis pathogen); pathogens of fusariosis are Fusarium okhusporum (Schl.), Snyd. et Hans., Fusarium graminearum Schwabe, Fusarium gibbosum App. et Wr., Fusarium solani (Mart.) Sacc.; Alternaria alternata (Fries: Fries) Keissler (Alternaria pathogen), Cladosporium cladosporioides (Fresen.) G.A. de Vries (cladosporiosis pathogen), Colletotrichum sp. (anthracnose pathogen); pathogens of various moulds – Aspergillus niger van Tiegh., Aspergillus flavus Link, Trichothecium roseum Link ex Friet Fries, Mucor mucedo Fres. amend. Bref., Penicillium expansum Link and Rhizopus nigricans Ehrenb. The dominant species were C. cladosporioides and A. alternata, their frequency of occurrence was in the range of 28.5-47.8%. The obtained data on the symptoms of mycosis of soybean seeds, the species composition of pathogens and their frequency of occurrence are of practical importance for the diagnosis of diseases, the identification of pathogens and the implementation of preventive therapeutic control measures