Articles
TIME OF HARVESTING AND DIPHENYLAMINE TREATMENTS IN THE CONTROL OF SUPERFICIAL SCALD IN APPLES CV. FUJI, IN RIO GRANDE DO SUL, BRAZIL
Fuji, harvested at three different times, were treated with diphenylamine, wettable powder (DPA-WP) and emulsion (DPA-E), at 800 and 1600 ppm, respectively.
They were stored at 0°C and 85–90% R.H. for seven months.
Afterwards, they were submitted to a simulated commercial period for ten days at 20–25°C. The incidence of superficial scald and maturity parameters such as firmness, soluble solids, iodine-starch, titratable acidity were evaluated at harvest and after cold storage.
Diphenylamine residues on apples after storage were also determined.
The greatest incidence of superficial scald was found at the first harvesting time (HT-1); it was 22.41%. It decreased to 9.31% at the second harvesting time (HT-2) and 8.54% at the third harvesting time (HT-3). It was observed that the incidence of superficial scald increased between the end of cold storage and the simulated commercial period.
All treatments controlled superficial scald, reducing to a level below 4.1%.
DPA-WP treatments presented greater residues level than DPA-E. The residues were as follows: 10.23 ppm and 4.78 ppm for DPA-WP 1 600 and DPA-WP 800; 1.29 ppm and 1.28 ppm for DPA-E 800 and DPA-E 1 600 respectively.
The maturity parameters showed an evolution in maturity stage at the three harvesting times and during cold storage.
The fruit did not show any skin injury or color changes with DPA treatments.