Influence of Bacillus bacteria strains on leaf-stem infections in cultivation of fruit-bearing strawberries

Abstract

In 2019–2021, field experiments proved the preventive effect of treating the aboveground parts of strawberry plants during the phenophase of the beginning of fruit filling with a mixture of Bacillus bacterial strains in liquid form (biopreparation Fitop 8.67) and dry form (Fitop 8.1) at concentrations of 1×104 CFU/ml and 1×105 CFU/ml on the prevalence of gray rot of fruits. On average, over 3 years of observations, against the background of artificial inoculation, the prevalence of gray rot decreased by 2.2–2.3 times (in the control 16.5 %), with a biological efficiency of 54–56 %; against a natural background – by 2.0–2.1 times (in the control 12.5 %), biological efficiency of 51–53 %. Against white leaf spot (ramularia) of strawberries on a natural infectious background in concentrations of biopreparations of 1×104 CFU/ml and 1×105 CFU/ml, the biological efficiency in variants with treatment with Fitop 8.67 was 23–25 % and Fitop 8.1 – 32–34 %. A decrease in yield losses from gray mold stimulated an increase in yield against the background of artificial inoculation with the pathogen of gray mold in variants using biopreparations Fitop 8.67 and Fitop 8.1 in concentrations of 1×104 CFU/ml and 1×105 CFU/ml to levels of 5.86–5.89 t/ha, economic efficiency of 11.0–11.4 %; against a natural background in the same concentrations – up to levels of 5.67–5.68 t/ha, economic efficiency of 7.6–7.9 %. The use of concentrations of 1×104 CFU/ml of both preparations Fitop 8.67 and Fitop 8.1 as alternative methods for protection against gray rot of fruits and white spot of leaves is promising in the technology of growing fruit-bearing strawberries.