Identification and species composition of pathogens of sugar beet storage-pile rot in short-rotation cropping systems of the Western Forest-Steppe of Ukraine

The relevance of the study is conditioned by the increase in phytosanitary risks due to the intensification of land use and reduction of crop rotation. The purpose of the study was to determine the species composition and population structure of fungal pathogens that affect beet roots during growth and storage. The study was conducted at the production fields of the private enterprise “Zakhidnyi Buh” using standard Mycological methods (isolation, morphological identification, calculation of the frequency of species occurrence). The species composition of the main pathogens of sugar beet storage-pile rot in short-rotation cropping systems of the Western Forest-Steppe of Ukraine, among which fungi of the genus Fusarium dominate, has been established. It was determined that five species of phytopathogenic fungi dominate short-rotation cropping systems: Fusarium oxysporum (30%), F. solani (18%), Phoma betae (19%), Rhizoctonia solani (13%), and Botrytis cinerea (10%). Total share of the genus Fusarium accounted for about 48% of all isolates, which indicates its leading role in the development of root and storage-pile rot. Significant morphological variability of isolates was found, in particular, variations in colony pigmentation and sporulation intensity, which confirms the high ecological plasticity of pathogens. It was shown that F. oxysporum and Phoma betae had the highest isolation frequency, while B. cinerea occurred mainly in conditions of high humidity. The results obtained indicate an increase in phytopathogenic load in short crop rotations and the development of stable fungal populations with high adaptive potential. The necessity for developing integrated sugar beet protection systems aimed at reducing the phytopathogenic load in short rotations was substantiated. The results obtained can be used in crop rotation planning, improving storage technologies, and introducing biological controls ( Trichoderma spp. antagonists)