Isolationand Identification of Antagonistic Bacteria Against Sporisorium scitamineum and Their Biocontrol Effect on Sugarcane Smut

Sugarcane smut is a fungal disease caused by Sporisorium scitamineum. To explore its biological control strategies, this study collected rhizosphere soil of sugarcane, isolated and identified biocontrol bacteria from it, and conducted multi-level control efficacy evaluations. The results showed that five bacterial strains with effective antagonistic activity against the sexual mating and teliospore germination of S. scitamineum were isolated and identified: 2143-2 (Pseudomonas baetica), 2143-4 (Bacillus subtilis), 2143-6 (Burkholderia diffusa), Y8-2 (Pseudomonas reinekei), and Y8-3 (Bacillus amyloliquefaciens). The results of the pot inoculation experiments showed that all five strains could prolong the incubation period of sugarcane smut and significantly reduce the disease incidence, demonstrating marked control effects, with strains 2143-4 and Y8-2 being the most effective. The results of the field inoculation experiments and natural field infection experiments indicated that strain Y8-2 exhibited the best biocontrol efficacy against sugarcane smut, with control efficacies of 68.40% and 73.99% in the field inoculation experiments, and 65.73% under natural field infection conditions. In addition, the biocontrol strains could improve the physiological stress-tolerance characteristics of sugarcane plants, which was conducive to enhancing the resistance of sugarcane plants to sugarcane smut.