Apple Maturity Report-Winchester Aug 18, 2021

DA readings refer to the level of chlorophyll (green color) in the fruit, just below the skin. As the fruit ripens, chlorophyll levels decline. Therefore, low DA values are indication of advanced fruit maturity. Starch index, fruit firmness, and, to some degree, Brix values are commonly used to determine the harvest date for most commercial apple varieties. Generally speaking, fruits intended for CA should be picked at starch index (3-5), firmness (> 16 lb), and DA reading (around 0.60). Fruits intended for fresh consumption should be harvested at starch index (5.5-7), firmness (13-16 lb), DA reading (0.35), and Brix (12-14%). 
Starch index was assessed for 12 apple varieties grown in the AHS Jr. AREC, Winchester, VA, on Aug 18
, 2021.
To get information about the starch index, iodine solution recipes, and different maturity indices please refer to our blog post at https://treefruithorticulturevaes.wp.prod.es.cloud.vt.edu/2012/08/23/harvest-maturity-resources/
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About S. Sherif

Dr. Sherif M. Sherif is an Associate Professor of Horticulture at the School of Plant and Environmental Sciences at Virginia Tech, USA. He received both his bachelor's and master's degrees in horticulture from Alexandria University, Egypt, and his doctorate in plant agriculture from the University of Guelph, Canada. Dr. Sherif's broad research experience in molecular biology, plant development, and tree physiology has led him to lead several research projects focusing on the biotic and abiotic factors affecting fruit trees' production, sustainability, and competitiveness. Sherif's current research program at Virginia Tech focuses on frost mitigation strategies, precision crop load management, high-density production systems, molecular regulation of critical horticultural traits, and germplasm development.