Removal of Sooty Blotch and Flyspeck from Apple Fruit with a Chlorine Dip. Floyd F. Hendrix, Jr., Research and Extension Plant Pathologist, University of Georgia, Athens, GA 30602. Plant Dis. 75:742-743. Accepted for publication 15 January 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0742.

Sooty blotch, caused by Gloeodes pomigena, and flyspeck, caused by Zygophiala jamaicensis, were removed from apple fruit with a postharvest chlorine dip. A 5- to 7-min dip in 500 ppm of chlorine in the dump tank of a commercial packing line, followed by brushing and a fresh water rinse, reduced the incidence of sooty blotch from 100 to 0% and flyspeck from 100 to 27%. Apples stored for 3 mo after removal of sooty blotch and flyspeck lost only 3.6–4.7% weight. Neither chlorine treatment nor waxing or brushing affected weight loss. Pesticide residues were reduced by the treatment. No phytotoxicity was observed on Red Delicious apple fruit exposed to 4,100 ppm of chlorine for 15 min, a level and treatment period far in excess of that required for effectively reducing disease incidence.