Scheduling adequate irrigation mitigates postharvest soft scald disorder of Ambrosia apples grown in a semiarid eco-zone

The effect of irrigation on soft scald (SS) disorder in Ambrosia (TM) apples was surveyed over 4 years in various orchards in Cawston, BC which is located in a valley having a semiarid eco-zone. The observations were further validated by manipulating irrigation programs in a series of experiments in three commercial orchards. Adequate irrigation (AI) was defined as the amount of water application required to maintain sustainable production as defined in the provincial irrigation guide, while deficit irrigation (DI) reduced irrigation to less than 40% of AI at the same site. Records from the survey study indicated that SS incidence was negatively correlated with the amount of watering (r = -0.9). The validation study confirmed that correlation at three different commercial sites. These results suggest that intensive water deficit can cause fruit to be susceptible to SS and that adequate watering during fruit expansion and late season exerts a mitigating effect on SS in Ambrosia (TM) apples grown in a dry climate region. They also suggest that conducting DI prior to midsummer does not irrevocably cause SS susceptibility in this apple.