GRAPE DISEASES drag down wine quality

摘要

Merlot wines from diseased fruit were lower in anthocyanins, phenolics, tannins, and alcohol. The effects of grapevine leafroll disease and other viruses on wine quality are real, not some vague generalities. Growers can easily see physical symptoms and notice production losses from viruses through declining yields, but declining wine quality often is not as easily noticed because vines maybe symptomless, and good and bad grapes are mixed together during crush. Washington State University plant pathologist Dr. Naidu Rayapati has collected extensive yield, fruit, and wine quality data in the last four years in side-by-side studies of diseased and normal vines in the same block, from different appellations, and of various cultivars. The results of hisstudies, the first of their kind, showed just how devastating grape leafroll and other viruses can be to Washington State vineyards.