Calcium chloride reduces rain cracking in sweet cherries

Rain cracking of sweet cherry fruit is a worldwide problem and has resulted in substantial crop losses of California cherries in each of the past 4 years (1993–1996). Various strategies to reduce cracking have provided inconsistent results. During 1996, however, rain-timed applications of calcium chloride (CaCl₂) via overtree sprinklers reduced the overall percentage of rain-cracked ‘Bing’ cherry fruit by nearly half at three locations in the Central Valley. Although these results were obtained in only one season, their consistency across sites is encouraging. In addition, a preliminary observation suggests this calcium treatment may also reduce postharvest disorders of rain-exposed fruit without affecting fruit firmness, size or weight. Some marginal leaf necrosis was noted at one site, suggesting that application rates may need to be adjusted. Overtree delivery of calcium chloride during rain provides the potential for cherry growers to reduce fruit cullage from rain. While the setup and operational costs are substantial, the increases in marketable fruit may make this system a profitable investment.