Downy Mildew Downy mildew is a major disease of grapes throughout the eastern United States. The fungus causes direct yield losses by rotting inflorescences, clusters and shoots.
Indirect losses can result from premature defoliation of vines due to foliar infections.
This premature defoliation is a serious problem because it predisposes the vine to winter injury. It may take a vineyard several years to fully recover after severe winter injury. Disease cycle of Eutypa Diaback. We wish to thank the New York State Agricultural Experiment Station for use of this figure. Figure taken form the Grape IPM Disease Identification Sheet No. 1.