Abstract
During the 2006–07 and 2007–08 fresh citrus seasons, reports of peel breakdown problems were more frequent and severe than usual. Plots were established during the 2007–08 season in commercial groves using standard fresh fruit growing practices to evaluate pre- and postharvest factors influencing peel breakdown. Preharvest treatments included up to three foliar potassium (K) sprays (March, October, and January) or withholding irrigation for up to 2 months before harvest. In one commercial block, foliar mono-potassium phosphate (MKP) was applied at 23.5 lb MKP per acre (0–52–34; 8 lb K2O per acre) with 4 lb per acre low-biuret urea (46–0–0) applied at a total volume of 125 gal per acre. In another block, the grower applied 3 gal per acre of a commercial 3–18–18 formulation at a total volume of 250 gal per acre. Postharvest treatments included holding fruit for 3 days at 30%, 55%, or 100% (including wetting the fruit) RH before washing and storing at 70 °F under ambient RH. In the first block, preharvest foliar MKP treatments applied 2 months or more before harvest did not significantly reduce peel breakdown. However, stem-end rind breakdown was significantly reduced in the second block with foliar 3–18–18 applied 2, 3, or 4 weeks before harvest. Blocking irrigation and rainfall for 49 days before harvest increased peel breakdown, whereas wetting the fruit after harvest and maintaining high postharvest RH reduced peel breakdown.
