Search articles from 1992 to the present. Sooty Blotch and
Flyspeck on Apple This article was published originally on
10/14/1994Sooty blotch and flyspeck are caused by different
fungi that commonly occur together on the same fruit. The sooty
blotch fungus causes superficial, black spots or blotches up to
1/4 inch or larger. These spots may merge, causing most the
apple to appear blackened. The flyspeck fungus causes clusters
of shiny round dots, each of which is about the size of a
pinhead. Pm- 673, "Recognizing common apple diseases in Iowa,"
shows a color photo of disease symptoms. Both diseases cause
superficial damage since the growth affects the cuticle of the
fruit. Vigorous rubbing will remove the blackened appearance.
These diseases are most prevalent when summer temperatures are
moderate and when extended wet periods occur. Several cultural
practices will aid in the control of sooty blotch and flyspeck.
Pruning, which facilitates drying by improving air flow, helps
to prevent extended wet periods. Pr