Promising Biocontrol Agents Against the Main Pathogens of Apple Fruit Rot

Current study looked into how well microorganisms, both those already known and newly found, from the surface of plants in gardens in southern and southeastern Kazakhstan could fight against other harmful microbes. We evaluated the effectiveness of 16 strains of lactic acid bacteria, 11 strains from the Bacillus and Pseudomonas genera, and 7 strains of Trichoderma fungi (all sourced from SPC Microbiology and Virology LLP), along with 135 epiphytic microorganisms, against four major rot-causing pathogens: Penicillium chrysogenum, Monilinia fructigena, Alternaria alternata, and Fusarium sporotrichioides. Out of 16 lactic acid bacteria strains, 11 showed antagonistic activity, primarily against M. fructigena, and to a lesser extent, other pathogens. Lactobacillus casei 32 exhibited the strongest inhibitory effect. Among the bacterial cultures screened, only the Bacillus amyloliquefaciens strain was found to suppress the growth of specific pathogens. Among the 7 fungal strains of the genus Trichoderma, 4 had significant antagonistic activity. The maximum zone of pathogen suppression was found in the strain T. asperellum 30. Screening of potential antagonist microorganisms from microbial populations isolated from the surface of apple fruits revealed that only 1 isolate of the bacterial flora had inhibitory activity against the pathogen M. fructigena. The following microorganisms with maximum antagonistic activity are promising biocontrol agents against fruit rot: Lactobacillus casei 32, B. amyloliquefaciens and T. asperellum 30.