The fungal diseases sooty blotch and flyspeck frequently mar the appearance of apples and pears, plums. Although these diseases usually occur together, they are caused by different fungi.

Both diseases can overwinter on a variety of woody plants. Disease development is favored by moderate temperatures (65°-75°F), high humidity, and abundant rainfall. Spores of sooty blotch and flyspeck are spread by wind or splashing water throughout the summer. Sooty blotch appears as black to brown, smudge-like spots on the surface of the fruit, while flyspeck forms clusters of pinpoint sized black dots (see figure).

The damage caused by sooty blotch and flyspeck is superficial. Infected fruit are safe to eat and the inside of the fruit is not affected. Proper pruning and thinning of the canopy, thinning of fruit clusters, and removal of nearby grass and weeds will improve air circulation and reduce disease. Regular application of fungicides, during the growing season, to prevent apple scab will also provide control of sooty blotch and flyspeck.

P226S
Revised 12/99
Chad Behrendt, Crystal Floyd