Inhibition of Citrus Green Mold Caused by Penicillium digitatum with Propolis Extracts

摘要

The antifungal activities of propolis extracts against Penicillium digitatum, the major cause of citrus green mold, were investigated. The results demonstrated that the inhibitory activities on mycelial growth of P. digitatum by propolis extracts with different polar solvents were in the order of propolis ethyl acetate extract (PEAE)=propolid ethanol extract (PEE) > propolis chloroform extract > propolis petroleum ether extract > propolis water extract, which were consistent with the contents of flavonoids or total phenolics in the corresponding extracts. Further investigation showed that the EC50 and EC90 for PEAE were 111 mg/L and 245 mg/L respectively, compared to 375 mg/L and 2612 mg/L for PEE. The PEAE also showed similar inhibitory effects on spore germination of the pathogen. Morphological observation demonstrated significant decrease in cytoplastic density with enlarged cytoplasts of hyphae of the fungi treated with PEAE. Furthermore, 0. 2% PEAE was effctive in controlling the citrus green mold caused by P. digitatum after artificial inoculation. Therefore, PEAE showed great potential to control postharvest decays of citrus.