Addressing the Gaps in our Knowledge of Grapevine Downy Mildew for Improved Forecasting and Management

Fig. 6. Mean relative severity of downy mildew on clusters of Vitis vinifera 'Chardonnay' and 'Riesling' and V. labrusca 'Concord' and 'Niagara' clusters inoculated at intervals starting at bloom in Geneva, NY, in 2002 and 2003. Severity was set equal to 1.0 at prebloom and bloom, and subsequent severity for each cultivar-year combination was scaled to that maximum. Data were pooled for intervals of 75 degree-days (base 10°C), which approximated 1 week intervals. Reprinted with permission from Kennelly, M. M., Gadoury, D. M., Wilcox, W. F., Magarey, P. A., and Seem, R. C. 2005. Seasonal development of ontogenic resistance to downy mildew in grape berries and rachises. Phytopathology 95:1445-1452.



Image from Plant Health Progress article:
Addressing the Gaps in our Knowledge of Grapevine Downy Mildew for Improved Forecasting and Management