Root rot of spring wheat in the Trans-Ural region, options for operational protection

Abstract. Root rot is a harmful and widespread disease of cereal crops. In the conditions of the Urals, Siberia, and Northern Kazakhstan, its causative agents are various species of fungi of the genus Fusarium and the fungus Bipolaris sorokiniana. The purpose of this study was to comparatively determine the effectiveness of microbiological, chemical and combined protection of spring wheat seeds. Field experiments were carried out on the experimental field of the Kurgan Scientific Research Institute of Agriculture – branch of the Ural Federal Agrarian Scientific Research Centre of the Ural Branch of the Russian Academy of Sciences (Kurgan SRIA – branch of FSBSI UrFASRC, UrB of RAS) in 2019, 2021, 2022. Scientific novelty lies in the determining the competitiveness of various methods of protecting spring wheat seeds in the conditions of the Trans-Urals within the framework of modern cultivation technology. The methods used are generally accepted in the Russian Federation. Results. In conditions of almost annual occurrence of negative natural phenomena for the growth and development of plants (droughts, frosts, sudden changes in temperature, dry winds, etc.), the use of seed treaters can be an additional stress for plants; the presence of the effect of shortening the underground internode can negatively affect field germination culture. To reduce these risks, as well as the pesticide load, we recommend using a combined method of seed protection. It involves the use of a mixture of a bacterial fungicide based on Bacillus subtilis with a chemical disinfectant at half the consumption rate. At the same time, the level of control of phytopathogens is maintained, there is no retardant effect, and economic efficiency is not inferior to the level of using a two-component chemical seed protectant (113–114 %). Chemical protection of seeds reduced the development of root rot pathogens by 63–72 %. The use of combined protection provided good control of phytopathogens, including the dominant fungi Fusarium. The predominant species from the genus Fusarium were the highly dangerous F. oxysporum, F. graminearum, F. sporotrichioides.