Biological Efficiency of Tank Mixtures of Preparations for the Protection of Spring Wheat and Their Effect on Grain Quality

In relatively favorable humidification years, the loss of spring wheat grain harvest from fungal infections – brown leaf and stem rust, powdery mildew, etc., has increased significantly, reaching 25–30% or more of the gross grain harvest. The purpose of the study conducted in 2018–2021 is to improve protection measures against harmful leaf–stem diseases in the conditions of the southern forest-steppe of  Western Siberia. Main tasks: monitoring the phytosanitary situation, studying the biological effectiveness of chemical fungicides, biological preparations, growth regulator and tank mixtures, including with liquid complex fertilizer, in spring wheat crops, determining the effect of various preparations on grain yield and quality. The study was conducted in short-term multivariate field experiments. The plot area is 25 m², the repetition is fourfold, the placement of options is randomized. The effectiveness of the drugs was compared with the control variant without protection from diseases. The use of chemical fungicides, tank mixtures of them with fertilizer, growth regulator in the sowing of spring wheat Omsk 36 provided a high level of biological effectiveness against leaf-stem diseases. The maximum efficiency indicators against brown leaf and stem rust were obtained with the use of tank mixtures of the drugs Soligor + Fast and Furious, Rex Plus + Larixin and Title Duo + Fast and Furious (98.4–99.7%). The best results of protection against powdery mildew were mixtures of drugs Rex Plus + Fast and Furious and Soligor + Larixin, respectively 78.8 and 81.2%. The greatest increases in grain yield to control were obtained in the variants of the use of the drugs Rex Plus + Larixin and Title Duo + Fast and Furious, respectively 1.80 and 1.89 t/ha. The level of economic efficiency in this case was more than 50%. The use of fungicides and tank mixtures significantly increased the nature and weight of 1000 grains. There was an increase in the gluten content from 1.2 to 5.1% in variants with the phytoregulator Larixin, protein – by 0.85–1.71%. In a field experiment similar to the scheme with Melody wheat, conducted in adverse weather conditions in 2020 and 2021, grain yield growth from the use of drugs was not obtained. The main reasons are the dry weather and, accordingly, the low incidence of diseases in the crop. Treatment with Larixin and its tank mixtures with Title Duo, Rex Plus and Soligor fungicides significantly increased the protein content in the grain by 0.80–1.50%, gluten – up to 2.0%. The obtained results testified to the high biological and economic efficiency of the use of modern fungicides and tank mixtures with a growth regulator and fertilizer in conditions of high infestation of spring wheat with leaf–stem diseases.