Postharvest preservation effect of composite biocontrol agent on tomatoes

Biological control has been highly sought after as an effective means of controlling postharvest diseases in tomatoes. In order to explore effective biocontrol bacteria for postharvest biological control, this experiment isolated and screened 3 bacterial strains with potential for biocontrol. These 3 strains were Bacillus velezebsis (WZ-37), Bacillus subtilis subsp.subtilis (WXCDD105), and Bacillus amyloliquefaciens (SS). The enhancer for different biocontrol bacteria were also screened, and the effectiveness of composite biocontrol agents was evaluated. The results showed that these strains had a good inhibitory effect on the occurrence of tomato postharvest gray mold disease, significantly reducing the disease incidence rate while enhancing fruit quality and preservation. Among them, WZ-37 showed the most outstanding biocontrol effect, while the composite biocontrol effect of SS+WZ-37 was the best. Each strain has its corresponding optimal enhancer, and the addition of enhancer can increase the concentration of biocontrol bacteria and improve the biocontrol effect. In this study, three synergists, 0.01% B1, 0.01% Thr, and 0.01% Met, were screened to have the best effect on our strains. After spraying the biocontrol agents, the water loss rate of the postharvest fruits was significantly decreased, and a biofilm formed on the surface of tomatoes effectively reduced the occurrence of diseases. Therefore, these strains have high applied value and promotional prospects, and can be used for postharvest disease biological control of tomato.