JMS stylet oil is one possible alternative, but our experience with it limited so it should be used with caution. Be sure to thoroughly read the label for possible interactions with other materials, especially sulfur and captan, before using JMS oil. Never use JMS oil within two weeks of a captan or sulfur application, and vice versa. It may not be necessary to apply fungicides post harvest. Growers should scout their plantings for problems to determine if fungicides are necessary.
Cultivars differ greatly in susceptibility to the common diseases.
For example, Chancellor and most vinifera cultivars are highly susceptible to both powdery and downy mildew and often require post-harvest disease control. Concord and Foch are only slightly susceptible to downy mildew and moderately susceptible to powdery mildew so seldom require post-harvest disease control. Other cultivars vary in relative susceptibility to diseases, and disease incidence and severity varies with the growing season. Apply fungicides only if necessary. Be sure to check for season limits on quantity of product allowed and read and follow all label recommendations.