Sooty blotch and flyspeck (SBFS) is a mid- to late-season disease of apple. SBFS fungi show up as dark smudges and clusters of black dots on the fruit surface. Since blemished fruit are downgraded, crop losses can exceed 90 percent of the fresh market value.
Iowa State University
Mayfield, Derrick A.; Gleason, Mark L.; and Batzer, Jean C., "Weather Inputs to a Warning System for Sooty Blotch and Flyspeck of Apple" (2012). Iowa State Research Farm Progress Reports. 51.