Investigations into the control of superficial scald in cool-stored Queensland grown Granny Smith apples by chemical means

Abstract

Experiments were conducted over a 5-year period to determine whether superficial scald in Queensland grown and cool-stored Granny Smith apples could be controlled by chemical means.
Diphenylamine applied prior to storage either as a dip or incorporated in paper wraps effectively controlled scald over a wide range of maturities and under conditions of normal atmosphere and controlled atmosphere storage.
Scald control was effected even in atmospheres containing high concentrations of carbon dioxide, but when 10 per cent. carbon dioxide was present in the, storage atmosphere, oiled paper wraps containing 15 per cent. mineral oil in addition to the diphenylamine treatment were necessary to obtain complete control.
Low concentrations of diphenylaimine in addition to oiled paper wraps containing 15 per cent. mineral oil yielded control of the disorder equal to higher concentrations of the compound used alone.
Though control was effected irrespective of the maturity of the fruit at the time of picking, other storage disorders increased if very immature fruit was stored.
Diphenylamine appeared to have some control on the incidence of internal breakdown in the experimental fruit.
A number of other chemical compounds were tested for their scald-controlling properties and five were found to give a considerable measure of control.