Efficiency of application of fungicides for spring wheat protection against root rots

Abstract

Infestation of grain crops by common root rot in the conditions of Ural Federal District was studied. In previous years, infestation of wheat by Bipolaris sorokiniana pathogens predominated, but in recent years, there has been a gradual shift in the structure of microbiocenosis with the prevalence of Fusarium spp. fungi. With zero and minimum grain crop tillage technologies (no-till, mini-till), chemical disinfection of seeds and fungicidal crop treatment becomes imperative. The efficiency and feasibility of using fungicides was studied on the seeds of spring wheat, cultivar Omskaya 36. Field experiments were conducted in the conditions of Kurgan region on leached chernozem in the period of 2009-2017. Yield losses caused by phytopathogenic fungi were largely determined by the hydrothermal conditions during the growing season. The largest damage to wheat productivity was caused by diseases of this group during dry periods (11% in years with satisfactory growing conditions, 22% in extremely dry years). It was discovered that the approach to protecting seeds from infections should be differentiated. Batches of seeds with high contamination by root rot pathogens are subject to mandatory chemical disinfection. Application of seed disinfectants based on two active agents is effective on wheat seeds infected by root rot pathogens over 15%, with the predominance of fungi genus Fusarium spp. Economic efficiency from the use of single-component seed disinfectants (tebuconazole, triticonazole) was 8-9%. When seeds were treated with seed disinfectants based on two active agents, the yield increased by 1416%. The use of systemic seed disinfectants is not recommended on relatively healthy seed material. It is more appropriate to use biological fungicide based on Bacillus subtilis.