Evaluation of phosphonate for control of postharvest mango pathogens

Field trials were carried out over two seasons at an orchard in southern Queensland, Australia, to investigate the effect of pre-harvest trunk injection and soil drenches of phosphonate on postharvest disease levels in mango cv. Kensington Pride. In the first trial, trees were injected when fruit were 'hen egg size'. Injection of a 400g/L formulation of potassium phosphonate (15 mL/m canopy diameter) significantly reduced postharvest stem end rot levels in fruit after storage at 22°C for 20 days. There was also a reduction in the isolation frequency of endophytic stem end rot pathogens from inflorescences ~ six weeks after injection, but this was not significant. In the second trial, injections and soil drenches were applied earlier in fruit development (flowering/fruit set stage). There was no reduction in fruit stem end rot levels. Results of the first trial suggest that further trials should be undertaken to investigate the potential of phosphonate for the control of postharvest mango pathogens