Physiological and physical measures to control postharvest diseases of fruit

Preharvest and postharvest decay of persimmon fruits caused byAltemaria alternata can be effectively alleviated by a growth hormone effect on the physiology of the fruit An orchard application of gibberellin (GA₃), prior to harvest, maintains the calyx in an upright, erect position, thus preventing the formation of a microclimate beneath the calyx, which is conducive to decay development in this region. The additional effect of delaying fruit maturation, leads to an increased resistance of the fruit to postharvest decay development on the entire fruit surface during storage. Other measures, of a physical nature, which can be employed to control postharvest disease, include a change in environment, such as achieved by controlled atmosphere storage or modified atmosphere packaging. The dominant control factors appear to be the naturally produced CO₂ and possibly acetaldehyde.