Studies on Application Strategy of Salts for Controlling Penicillium Rot of Valencia Late Oranges

摘要

For a more rationale utilization of alternative control means of postharvest diseases, different strategy of application needs to be evaluated. The results on the efficacy of five inorganic salts in controlling postharvest Penicillium rot of Valencia late oranges are reported. Aqueous salt solutions (2% , w/v) were applied i) by spraying before harvest, ii) by dipping after harvest and iii) by a combination of the two application types, simulating commercial conditions. Preharvest sprays and the combination of pre and postharvest application were in average more effective in suppressing Penicillium rot than the postharvest dipping. In particular, in preharvest applications Na-bicarbonate significantly reduced the percentage of rotted fruit (- 100% ), being as effective as Imazalil treatment, followed by Kbicarbonate and K-carbonate (- 86% ). In combined applications, all salts were effective in reducing Penicillium rot as compared to the water control, with a complete disease suppression by Na-carbonate and K-carbonate. Concerning the postharvest application, none of the compounds was as effective as the fungicide, although K-carbonate significantly reduced the infection by 75% , as compared to the water treated control. The results clearly demonstrate that the use of salts for controlling postharvest Penicillium rot of citrus needs a different strategy of application as compared to the chemical fungicides.