Sooty blotch and flyspeck

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Sooty blotch and flyspeck (SBFS) is a cosmetic disease of apples and other fruits caused by many saprophytic fungi living on the waxy surface of the fruit. It creates dark, soot-like smudges and tiny black dots that can rub off, leaving the fruit’s peel looking blemished but not damaged. The problem is more noticeable on light-colored apples and can cover large areas if conditions are right. The fungi don’t invade the fruit flesh.

Infections happen mainly in cool, moist weather from June through autumn. Shade, morning dew, and proximity to water make orchards more prone. Signs usually appear about three weeks after infection. The fungi survive on the surface and on wild plants, and the complex includes many species that vary by region. Flyspeck is caused by Schizothyrium pomi; sooty blotch involves other related fungi. The two often occur together and are called SBFS.

Management focuses on improving fruit drying and air circulation: prune to increase light and airflow, especially in damp areas. In conventional orchards, treating for apple scab also helps reduce SBFS. Organic controls include lime sulfur or coco soap during the main infection periods. A risk model called Sooty Blotch RIMpro helps predict infection risk to guide spraying. The damage is cosmetic, lowering market value, but does not affect fruit growth or health.