Sooty blotch and flyspeck are diseases of apples which result from fungi colonizing the fruit surface without penetrating below the peel. These fungal colonies simply grow on the surface of the apple. However, consumers don’t want to purchase apples with any blemishes. As a result, numerous fungicide sprays are used to prevent the fungal colonies and meet consumer demands.
“Sooty blotch and flyspeck (SBFS) is a disease caused by a complex of saprophytic fungi that colonize the epicuticular wax layer of apple and several other fruit crops in humid production regions worldwide. In the eastern half of the continental United States, SBFS is a major problem for commercial apple growers because the dark blemishes of SBFS colonies result in downgrading fruit from fresh-market to processing use, with economic losses as high as 90%
To suppress SBFS and fruit rots, most apple growers in this region apply fungicide sprays every 1 to 2 weeks from 7 to 10 days after petal fall until shortly before harvest.”
Authors: Diaz Arias, M.M., et al.
Affiliation: Department of Plant Pathology, Iowa State University
Title: Diversity and Biogeography of Sooty Blotch and Flyspeck Fungi on Apple in the Eastern and Midwestern United States.
Source: Phytopathology. 2010. 100(4):345-355.