ASSESSING THE EFFECT OF TWO STRAINS OF ENDOPHYTIC BACILLUS BACTERIA ON THE COMPOSITION OF THE INTERNAL MICROFLORA OF SPRING WHEAT PHYTOPHAGES

The article presents research materials on assessing the effect of treating spring wheat seeds and plants with biopreparations based on two endophytic bacteria Bacillus mojavensis PS17 and Bacillus amyloliquefaciens RECB-95 on the species composition and quantity of the internal microflora of such phytophages as wheat thrips (Haplothrips tritici) and striped grain flea beetle (Phyllotreta vittula). Spring wheat was cultivated in Laishevskiy district of the Republic of Tatarstan during three growing seasons from 2020 to 2022. The stationary field experiment design included the study of the following options: control (no treatment); seed treatment with PS17 at a dose of 0.5 l/t + plant spraying with PS17 at a dose of 0.5 l/ha; seed treatment with PS17 at a dose of 1.0 l/t + plant spraying with PS17 at a dose of 1.0 l/ha; seed treatment with PS17 at a dose of 1.5 l/t + plant spraying with PS17 at a dose of 1.5 l/ha; seed treatment with RECB-95 at a dose of 1.0 l/t + plant spraying with RECB-95 at a dose of 1.0 l/ha; seed treatment and plant spraying with chemical fungicides. The objects of the research were phytophagous insects (striped flea beetle and wheat thrips) living on spring wheat of Ulyanovskaya 105 variety. Wheat was cultivated in gray forest soil with the following agrochemical parameters: initial humus content of 3.2% (according to Tyurin), mobile phosphorus and potassium (according to Kirsanov) – 233-240 mg/kg of soil, and 176-189 mg/kg of soil, pH of salt - 5.7. The experiment was repeated three times, the plots were placed sequentially, the area of each plot was 110 m2. The system of primary and pre-sowing soil preparation included stubble cultivation, plowing, pre-sowing and post-sowing harrowing, pre-sowing application of azophoska at a dose of 150 kg/ha. During the studies, a decrease in the number of microorganisms in the body of the striped grain flea beetle was noted from 14.50 - 18.40 CFU×104 (in the untreated control variant) when using the PS17 strain to 0.10 - 0.20 CFU×104 (at a dose of 1.0 l/t) and to 4.73 CFU×104 when using the RECB-95 strain; in the body of the wheat thrips, an increase in the number of microorganisms was noted from 1.94 CFU×104 (in the untreated control variant) to 3.20 - 7.20 CFU×104 when using the RECB-95 strain. A change in the species composition of microorganisms, both fleas and thrips, was also noted when using both biological products.