The influence of biofungicide and chemical fungicides on the manifestation of diseases and the yield of soybeans

This study aims to improve the technology for protecting soybeans from fungal diseases based on new fungicides. The relevance of research is specified by a significant increase in the area occupied by soybeans and the need to protect crops from diseases. The experimental site is located in the territory of Oryol State Agrarian University (Lavrovo village of Oryol Region, Russia). The crop rotation is grain-fallow, the predecessor is winter wheat. The soil type is dark gray forest medium loamy. Soil acidity is 5.7. It has the following content of macronutrients: 11.5 mg/100 g of soil for P2O5, 10.9 mg/100 g of soil for K2O, 4.1% for humus. The Mezenka soybean was used, seeds of the 1st reproduction. Planting was carried out in the first decades of May 2019 and 2020. We used the Maksim, KS protectant (Fludioxonil, 25 g/l). Fungicides Propuls, SE (Prothioconazole, 125 g/l, Fluopyram, 125 g/l), Vintazh, ME (Difenoconazole, 65 g/l, Flutriafol, 25 g/l) and biofungicide Vitaplan, SP (Bacillus subtilis strain VKM-V-2604D, titer 1010 CFU/g and Bacillus subtilis strain VKM-B-2605D, titer 1010 CFU/g) were used to treat plants at the end of June in the branching phase and again two weeks later in July in the budding phase. The treatment of soybean seeds with the fungicide Maksim, KS helped to protect the crop from fungal diseases until the first ten days of July. Two-fold treatment of crops with biofungicide Vitaplan and chemical fungicides Propuls and Vintazh had a significant impact on the prevalence and development of fungal diseases. The biological effectiveness of chemical fungicides in comparison with biological was higher in the phase of complete formation of beans - the beginning of ripening by 9 and 15%, respectively. In comparison with the control, the increase in the yield of soybeans was 10.4% using Vitaplan, 16.4% using Propuls, 17.9% using Vintazh.