Control of stem-end rot of mango by heat treatment of the peduncle

Abstract

To develop an effective method for controlling post-harvest stem-end rot of mango, we investigated the efficacy of heat treatment of mango peduncle using a soldering iron. Examination of pathogen progression from the peduncle to fruit interior in fruits of varying degrees of maturity revealed that the pathogen developed more quickly in mature fruit than in immature fruit, with the pathogen in the former advancing to a depth of 15 mm from the peduncle 12 h after inoculation with the pathogen. Heat treatment of the peduncle was accomplished by cutting the tip of the soldering iron flat and pressing the heated tip against the peduncle for 10 s. Following heat treatment of peduncles 3, 6, 12, or 24 h after inoculation with the pathogen, disease was significantly inhibited only in fruits that were heat treated 3, 6 or 12 h after inoculation, but not in those that were heat treated 24 h after inoculation. These results demonstrated that it is necessary to perform heat treatment of peduncles within 6 h of harvest in order for the treatment to be effective. In addition, in field experiments in which peduncles were heat treated 4 h after harvest, we observed marked inhibition of disease in heat-treated fruit compared to untreated fruit, with no deterioration in quality of heat-treated fruit.