Phytopathological examination of spring grain seeds
Problem and purpose. The largest share in the structure of sown areas of Ryazan region is occupied by grain crops, which on average over 5 years amounted to 57.5% with a tendency to increase (500.3 thousand hectares in 2017 and 628.1 thousand hectares in 2021). Saturation with grain crops contributes to accumulation of infection and deterioration of the phyto-sanitary state of crops. Losses in crop yields from disease can range from 20% to 70%, with more than 60% of pathogen species transmitted through seeds. An effective method of reducing the spread and development of pathogens is seed dressing, the effectiveness of which, first of all, depends on the correct choice of preparations. The decision on the advisability of pre-sowing seed treatment and selection of a disinfectant with the required spectrum of action is possible only if there is information about seed contamination. The purpose of the study was to conduct a phyto-pathological examination of seeds to determine the species composition of pathogens and the degree of seed infestation of spring crops with seed infection in order to improve their sowing and phyto-sanitary qualities, and as a result, grain yield. Methodology. The objects of study were seeds of spring wheat, spring barley, and oats. Phyto-expertise was carried out in 2017-2021 in Ryazan region and concerned 112.04 thousand tons, which accounted for 46.11% of the total amount of seed material. Assessment of the phyto-sanitary state spring crop seeds was carried out in Ryazan region in 2017-2021 using the methods reflected in GOST 12044-93 "Seeds of agricultural crops. Determining the infestation with diseases was carried out by employees of the plant protection department of the branch of Federal State Budgetary Institution "Rosselkhozcenter" in Ryazan region and Federal State Budgetary Educational Institution of Higher Education RSATU. Results. Analysis of the level of infestation of seeds of spring grain crops with individual pathogens in 20172021 in Ryazan region showed that Alternaria blight and Helminthosporium disease were most widespread. Infection of seeds of spring grain crops with Alternaria blight over the years of research amounted to 109.1 thousand tons, and that with Helminthosporium disease was 84.51 thousand tons of the volume of phyto expertise. The percentage of seed infestation with Alternaria blight varied in spring wheat from 28.99% to 62.31%, in spring barley from 36.62% to 68.23% and in oats from 41.55% to 49.25%. Seed infestation with Helminthosporium disease was lower than with Alternaria blight - 6.5% -32.82%, depending on the year and crop. To a lesser extent, seeds of grain crops were susceptible to fusarium infection. The total weighted average percentage of infection with diseases of spring grain crops for the study period was 78.21%. The maximum weighted average percentage was observed in 2021 and amounted to 85.26%, and the minimum weighted average percentage in 2018 was 61.14%. The seed material of spring barley was most susceptible to various pathogens. Conclusion. Analysis of the grain crop seed materials in Ryazan region showed that the level of infestation of seeds was quite high. Seed treatment is necessary to protect seeds and seedlings from damage by phytopathogenic fungi located on (in) the seed (s) and living in the soil. The use of systemic preparations to treat seeds of an average degree of infestation with pathogens allows to save 11-22% of the crop and biological products save 4-11%.