Isolation and Identification of Anthracnose Pathogen in Postharvest Papaya Fruits and Screening of the Antagonistic Bacteria

The anthracnose pathogen was isolated from the infected papaya fruits,the antagonistic bacteria W-2 was screened from the soil in papaya orchard by the method of flat-stand method and the filter paper method. Both the pathogen and antagonistic bacteria were identified by morphological and molecular biological methods. The antagonistic activities of W-2 were studied preliminarily. Results showed that the pathogen was identified as Glomerella magna and the antagonistic bacteria was Bacillus atrophaeus. Enlarged mycelia and deformed spores were observed by the action of W-2.Moreover,the mycelial growth were inhibited at the concentration of 1×10⁸ CFU/mL,and spore germination were inhibited significantly(P<0.05)at the concentration of 1×10⁸ and 1×10⁹ CFU/mL. The in vivo test showed that the lesion diameter in papaya fruits was suppressed by W-2 at the concentration of 1×10⁸ CFU/mL,and the disease incidence of fruits was reduced significantly(P<0.05).