Remove weeds and tall grasses from the planting and surrounding areas to improve air circulation. Prune vines early in the growing season after the danger of severe cold winter temperatures is past. Select only strong, healthy canes of the previous year's growth. Remove prunings from the vineyard and dispose properly. Select a planting site where vines receive full sun with good air circulation.
Space vines properly in the row and keep canes off the ground.
Grape varieties differ in their susceptibility to downy mildew so chose varieties with more resistance. Fungicide controls are effective for downy mildew if the plants are adequately protected with fungicide during prolonged rainy periods. If the disease has been severe apply an additional spray when the shoots are 6 inches long. Based on material developed in 1994. Lawrence K. Forcier, Director, University of Vermont Extension, Burlington, Vermont.