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Disease Control and Pest Management

Calcium Infiltration of Golden Delicious Apples and Its Effect on Decay. W. S. Conway, Horticultural Crops Quality Laboratory, HSI, ARS, S&E, U.S. Department of Agriculture, Beltsville, MD 20705; C. E. Sams, Horticultural Crops Quality Laboratory, HSI, ARS, S&E, U.S. Department of Agriculture, Beltsville, MD 20705. Phytopathology 73:1068-1071. Accepted for publication 15 February 1983. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/Phyto-73-1068.

Golden Delicious apples were treated with 0, 2, 4, 8, or 12% solutions of calcium chloride by dipping, vacuum infiltration (250 torr), or pressure infiltration (68.95 kPa). One lot of apples was inoculated with a conidial suspension of Penicillium expansum immediately after treatment, and a second lot was placed in storage for 5 mo at 0 C, removed, and inoculated in the same manner as the first lot. Inoculated apples were stored for 7 days at 20 C, then were rated for decay severity and analyzed for calcium content and water-soluble polyuronides. The smallest area of decay, the fewest water-soluble polyuronides, and the highest amount of calcium in tissues were found in the apples that were pressure infiltrated with 12% calcium chloride. However, apples stored for 5 mo after treatment by vacuum or pressure infiltration of 8 or 12% solutions of calcium chloride showed peel injury. The optimum treatment, which reduced the area of decay by 30% and resulted in no peel injury, was pressure infiltration of a 4% calcium chloride solution.