Although grape sour rot can occur in drier climates, the disease complex tends to be especially problematic during wine grape ripening in wet, humid regions. Browning and disintegrating berries and the aroma of vinegar (acetic acid) are a few symptoms that characterize grape sour rot. Sour rot ultimately results in crop yield reduction as damaged berries often “shatter,” or fall off the clusters. Sorting out clusters with sour rot that are not suitable for winemaking causes a further reduction in return revenues as less wine is produced. Although it has only recently been a topic of defined research, sour rot is a prominent concern in Eastern U.S. vineyards as: (1) it is consistently observed in vineyards, particularly in white-berried cultivars; and (2) questions remain about how to best manage it, particularly with the threat of insecticide resistance development in targeted fruit flies.
Status and Revision History
Published on Sep 28, 2020