Effect on stem-end rot and anthracnose levels of dipping mango fruit in host-defence-promoting compounds

摘要

Anthracnose and stem-end rot are the major postharvest diseases of mango. The causal pathogens may infect fruit in the field and remain latent during subsequent fruit development.Both diseases are usually controlled by pre-and postharvest fungicide treatments. However, in view of public concern about health risks and the possibility of pathogens developing resistance to fungicides, it is important to explore alternative control measures. To this end, an experiment was conducted to determine if treatment with the host-defence-promoting compounds, salicylic acid and potassium phosphonate, would induce fruit resistance to stem-end rot and anthracnose. Mango cv. Kensington Pride fruit were treated with 0, 10, 100, and 1000 mg/L salicylic acid or potassium phosphonate as a series of three preharvest dips and one postharvest dip. Ripening (colour, firmness) and disease (severity, incidence) parameters were assessed at various intervals during shelf life at 23deg C. Neither salicylic acid nor potassium phosphonate treatments reduced disease incidence or severity under the conditions of this experiment. For both pathogens, disease symptoms (lesions) appeared when the fruit started to ripen, as indicated by colour and firmness changes, There were no significant treatment effects on colour or firmness changes.These results suggest that salicylic acid and potassium phosphonate did not induce host resistance mechanisms.