`Fuji' apples grown in the high light intensity of arid eastern Wash. are prone to sunscald damage. Evaporative cooling with over-tree sprinklers has become a commercially acceptable method for reducing the incidence of sunscald damage. A computer-controlled, over-tree evaporative cooling system was installed in a 3-yr-old commercial `Fuji'/M.9 orchard near Walla Walla, Wash. Over-tree sprinklers (Nelson R10 Mini Rotators) applied 280 or 560 1·min-1·ha-1 (30 or 60 GPM/A) when core temperatures were ≥33C (91.4F). Fruit skin and core temperatures were monitored with thermocouples. Fruit growth was not different between treatments. Skin color was improved by cooling, but the incidence of sunscald was low in all treatments. Commercial pack-out was measured and culls were evaluated. Fruit quality was analyzed at harvest and after 14 weeks storage. Titratable acids and soluble solids were higher in the 560 1·min-1·ha-1 treatment at harvest.
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