Assessing the risk of superficial scald developing
In order to avoid the unnecessary application of post-harvest chemical treatments to apples the risk of disorders should be established for each consignment of apples. The risk of superficial scald is influenced by climatic conditions during fruit development; hot dry conditions are generally conducive to scald development during storage.
Although formulae to predict scald in Bramley apples have been developed, these are of limited practical use at the present time. These relate to fruit stored in ventilated CA conditions of 8-10% CO2 (11-13% O2) where the risk of scald is high compared with scrubbed, low oxygen storage.
Further work is required to increase robustness of scald prediction models for storage in ventilated CA storage. These need to include the marked effects of harvest date on scald potential (early harvested fruit are more likely to develop scald) and the effects of store air circulation, position of fruit within bins and position of bins within the store.
- Until the influence of all these factors on scald development have been resolved and included in a prediction model the advice to growers is to rely on the use of SmartFreshTM or ethylene scrubbing to gain control of superficial scald.
- With Bramley , growers can also employ scrubbed, low-oxygen conditions of 5% CO2 + 1% O2 (5/1) to gain control of scald.