Dynamics of stem end rot disease of mango fruit and its management

Stem end rot (SER) is a fungal disease complex that poses a major threat to the delivery of quality mangoes from Pakistan to export markets. The dynamics of this disease remain unclear but must be elucidated so that effectiveness of disease management can be improved. The present study sought to describe the infection process and delineate a disease cycle of SER under Pakistani growing conditions. Our study discovered three possible routes of infection that could lead to SER: 1) infection at bloom stage; 2) the pathogen may be endophytic within the twigs and branches; and 3) airborne spores of the pathogen invade the pedicels and xylem and then grow into the ripening fruit. Culturing of symptomatic samples from selected orchards revealed colonization by five fungal pathogens, of which Lasiodiplodia theobromae was most prevalent. A pathogenicity assay revealed that all five pathogens were pathogenic to mango fruit when inoculated artificially. The efficacy of fungicides – Cabrio Top at the rate, Nativo at the rate, Scholar at the rate, Tecto at the rate, Amistar at the rate, and Sportak at the rate at several concentrations was evaluated against SER pathogens in vitro and in vivo. Results indicated that Nativo®, and Cabrio Top at the rate, at 250 mu g/mL provided statistically significant suppression of mycelial growth and SER development as compared to other tested fungicides. (author)