Effect of particle film on fruit sunburn, maturity and quality of 'Fuji' and 'Honeycrisp' apples

Studies were initiated in Idaho and New York to determine the effects of Surround, a kaolin clay particle film product recently labeled as a crop protectant for agricultural crops, on fruit maturity and quality of 'Fuji' and 'Honeycrisp' apples (Malus x domestica) and fruit mineral concentration of 'Fuji' apples. Surround reduced fruit weight, red color, and the incidence of sunburn of 'Fuji' apples in Idaho. Sunburn did not occur on 'Honeycrisp' in the New York study. In that study, Surround had no effect on fruit weight or red fruit color when applied in May and June but reduced fruit weight and red color when applied later. The reduction in red color development observed in both 'Fuji' and 'Honeycrisp' was not related to mineral nutrients or to a delay in fruit maturity. Surround applications resulted in undesirable residues in the basin and in the cavity of harvested fruit that were not satisfactorily removed by brushing on a commercial packing line. While effective for reducing sunburn, Surround was ineffective for increasing red fruit color of apples.