Antifungal activity of Tupistra chinensis extract against Colletotrichum musae of postharvest banana

To explore plant extracts as antifungal agents for the postharvest diseases control of banana, the antifungal activities against Colletotrichum musae in vitro of the methanol extract, its ethyl acetate fraction and n-butanol fraction of the rhizomes of Tupistra chinensis were evaluated by spore germination and mycelial growth rate. The stability of antifungal activity of the n-butanol fraction of the methanol extract resisting high temperature(121℃ for 20 min), UV irradiation(30 W for 15 h, 50 cm vertical distance) and acid (pH=3) was investigated. Furthermore, the storage experiments of postharvest banana fruits dipped in the solutions of methanol extract and its two fractions were carried out separately. Results show that the EC₅₀ values of methanol extract, its ethyl acetate fraction and n-butanol fraction inhibiting the spore germination of Colletotrichum musae are 1490.27, 638.40, 1112.65 μg/mL, and the EC₅₀ values inhibiting the mycelial growth of Colletotrichum musae are 1262.16, 451.02, 955.58 μg/mL, respectively. Treatment of high temperature, strong acid and UV irradiation do not affect the antifungal activity of the n-butanol fraction of the methanol extract of Tupistra chinensis against Colletotrichum musae. Application of the methanol extract, its ethyl acetate fraction and n-butanol fraction lead to a significant decrease in the incidence of latent anthracnose during storage of postharvest banana fruits.