Lack of fruit could result from improper pruning. They must be pruned yearly during dormant season. Method of pruning, long cane or spur, will depend on the grape variety. Fruit will grow on shoots from last year s fruiting canes. There are several Catawba, Cherokee, and Seminole that are resistant to this fungus.
Cultural practices are also important.
Plant Crape Myrtle in a sunny location with good air circulation. Avoid excessive fertilizer and irrigation, which promote new, susceptible growth. Do not prune during hot weather but during dormancy, prune out and dispose of any infected tissue.