Further investigations of a method of controlling apple scald with diphenylamine emulsions

摘要

Abstract Diphenylamine (DPA) in an emulsion was applied as a post-harvest spray to S varieties of apples, each harvested at 3 stages of maturity. Uptake of DPA by the fruit varied with variety, its maturity at harvest, and the duration of the spray application. Adequate control of the most common scald symptoms was obtained on all varieties with a DPA uptake of less than 5 μg/cm2. This can be achieved by spraying for a period of between 1 and 2 min. Certain scald-like symptoms on Granny Smith and Sturmer Pippin did not readily respond to DPA treatments. Damage due to treatment was observed on Dougherty, while a naturally occurring browning of lenticels on the variety Rome Beauty was aggravated by treatment.