Nowadays, thanks to organic farming development, particular attention is paid to the biological methods of plants protection, especially from diseases. Therefore, new biological preparations creation and studying their effectiveness are promising directions. The aim of the research was to study the antagonistic activity of the bacteria Paenibacillus polymyxa and Bacillus amyloliquefaciens against some phytopathogens (Pseudomonas syringae van Hall, Fusarium oxysporum Schltdl, Alternaria alternata (Fr.) Keissl.), as well as their reaction to laser irradiation. The research was carried out in the Research Problem Laboratory “Biphotonika” of the Michurinsk State Agrarian University and the Department of Agricultural Microbiology of the Research Institute of Agriculture of Crimea in 2016–2021. The antagonistic activity of the bacteria was evaluated by the double culture method. The effectiveness of irradiation (as a result of their treatment with coherent light) was determined by the change in the number of bacterial cells in the suspension. The study of the activity of bacteria-antagonists against pathogens showed that the suppression of P. syringae, F. oxysporum, A. alternata growth in the double culture with P. polymyxa compared to the control variants was 32.5 %; 4.0 % and 77.9 %, respectively. B. amyloliquefaciens suppressed the growth of P. syringae by 25.9 %, F. oxysporum – by 49.0 %; A. alternate – by 61.1 %. An increase in the number of cells in suspensions of P. polymyxa and B. amyloliquefaciens after coherent light irradiation by 26.6 % and 36.7 %, respectively, was also found. Thus, to control P. syringae, bacterial strain of P. polymyxa P was more effective. The bacterial strain B. amyloliquefaciens 01-1 showed antagonistic activity against F. oxysporum. Both studied microorganisms were effective against A. alternata. To increase the activity of cell division of antagonist strains of phytopathogens, it is advisable to use coherent light irradiation. In future, it is advisable to test the level of antagonistic activity of the bacteria P. polymyxa and B. amyloliquefaciens after laser irradiation.
The synergistic effects of Spirulina platensis and Bacillus amyloliquefaciens on the growth performance, intestinal histomorphology, and immune response of Nile tilapia (Oreochromis niloticus)
