In Vitro Evaluation of Lactobacillus sp. as Biological Control against Crown Rot Pathogens in Cavendish Banana (Musa acuminate)

Cavendish banana (Musa acuminata) is one of the most globally traded fruits; however, postharvest losses due to crown rot, primarily caused by Fusarium spp. and Colletotrichum musae, pose significant challenges. This study evaluated the efficacy of Lactobacillus sp. as a biological control agent against these fungal pathogens in vitro. Gram staining confirmed that Lactobacillus sp. is Gram-positive, as its cells stained purple under the microscope. A catalase test further revealed that Lactobacillus sp. is catalase-negative, as no bubbles formed upon exposure to hydrogen peroxide, in contrast to the catalase-positive Ralstonia solanacearum. The antagonistic potential of Lactobacillus sp. was tested against Fusarium spp. and C. musae using different concentrations (5, 10, and 15 ml/L), compared to a synthetic fungicide (Prochloraz) and a control (PDA only). Growth of Fusarium spp. was significantly suppressed at concentrations of 5 and 15 ml/L, with complete inhibition observed at 10 ml/L. Similarly, C. musae growth was reduced by 94.1% at 10 ml/L and 83.1% at 15 ml/L, while 5 ml/L resulted in only 36.5% inhibition. These results were analyzed using ANOVA followed by a post-hoc test at the 5% significance level (p < 0.05), indicating that higher concentrations of Lactobacillus sp. are more effective. Lactobacillus sp. significantly inhibited fungal growth, showing comparable efficacy to synthetic fungicides. These findings highlight the potential of Lactobacillus sp. as an eco-friendly alternative for managing crown rot in bananas.