Importance of different sources of inoculum and dispersal methods of conidia of Colletotrichum musae, the causal agent of banana anthracnose, for fruit contamination

Different populations of Colletotrichum were characterized and quantified o n floral parts of banana plants from flowering until harvest. Isolates of C olletotrichum found to be pathogenic and attributed to the species C. musae (77% of isolates) were differentiated from other species by abundant sporu lation, a short mycelium, and rapid growth. Colletotrichum musae was isolat ed from floral parts mainly during the month following bunch emergence. The respective involvement of different sources of inoculum (leaves, bunch bra cts, floral parts) in the levels of fruit contamination was evaluated. When the floral parts and bunch bracts were removed at flowering, the severity of anthracnose disease was considerably reduced. The severity of the diseas e is strongly correlated with cumulative rainfall during the first 35 days after bunch emergence, and was considerably reduced when rainwater runoff o ver the bunches was limited by placing plastic sleeves over them. The disea se was not observed on banana fruit grown under shelters, protected from ra in. The results obtained from this study show clearly that contamination of fruit by conidia takes place largely due to the trickling of rainfall over the floral parts, which are the main source of inoculum. The application o f these results for integrated control is discussed.