White rot is often referred to as Botryosphaeria rot or Bot rot and is caused by Botryosphaeria dothidea, a serious fungal pathogen of apple fruit and wood. The fungus causing white rot is ubiquitous in nature, occurring on a wide variety of woody plants including birch, chestnut, peach, and blueberry. Fruit rot infection is most common in areas of the southeastern United States where losses of up to 50% have been reported. The canker phase of the pathogen can also cause considerable loss in many regions of the South, Midwest, and Northeast. Drought stress and winter injury have also been associated with an increase in infection and canker expansion. Read this article on White Rot for images and more information.
Answer provided by Alan R. Biggs, West Virginia University.