Improvement of the phytosanitary condition and productivity of potatoes under the influence of promising strains of bacteria of the genus Bacillus

Relevance. Chemical pesticides are currently used to protect potatoes from diseases. Their main advantage is efficiency, mass scale and speed. The main disadvantage is the dangerous to human life and warm-blooded animals toxic effect, as well as the death of beneficial insects (bees, bumblebees) pollinating plants. In addition, most harmful bacteria and fungi develop resistance to chemicals, forcing manufacturers to create new, increasingly toxic drugs. To solve this problem, it is of paramount importance to improve the technology of potato cultivation in the direction of its biologization, that is, the search for biological agents, the creation and use of biological agents on their basis for protecting potatoes and obtaining environmentally friendly products. Methods. The aim of the study was to evaluate the growth-stimulating and antifungal action of bacteria of the genus Bacillus on potatoes of the Tuleyevsky variety. The results of field experiments are presented for the period 2019–2020. The experiments were conducted in the Novosibirsk region, g, Novosibirsk, UPH “Garden of Michurintsev” of the Novosibirsk State Agrarian University. To improve morphometric parameters and reduce the prevalence of rhizoctonia, potato tubers were treated with strains of the bacterium of the genus Bacillus: B. thuringiensis ssp. morrisoni; B. thuringiensis ssp. dacota; B. subtilis; B. liheniformis. Phytosporin-M, P (B. subtilis strain 26 D) was used as a reference. Results. The best results (on average for 2 years) were seen in the variant using the B. subtilis strain, which provided an increase in plant biomass by 1.7 (2019) and 1.2 (2020) times and the number of stolons by 43% compared to the control variant. The use of the strain B. thuringiensis spp. dacota in 2019 provided an increase in the length of the ground part by 10%, by 1.2 times-the number of stems and by 1.6 times — stolons. The prevalence of the causative agent of the black scab in all periods of accounting decreased by 1.7–3.7 times compared to the control in variant B. subtilis, and on the 10th week of accounting — in 3.5 (2019) — 2.6 (2020) times relative to the  standard. The use of bacterial strains allowed us to achieve a higher quality and higher yield compared to the control version and the standard. When using strains of B. thuringiensis ssp. morrisoni and B. thuringiensis ssp. dacota in 2019, the yield increased by 1.4 and 1.5 times, respectively, and in 2020, with the strains of B. subtilis and B. thuringiensis ssp. morrisoni — by 1.2 and 1.3 times respectively.