Answer: As you have already realized, sanitation is very important in reducing reinfection. Additional steps would include proper pruning and possibly preventive spraying. Pruning should be done in late winter and involves cutting the vine back very hard, in most cases to just a few buds. (The trimmings are then removed and destroyed.) This would allow you room to work on the arbor as well.
A spray routine would depend on the incidence of specific problems in your area as well as the built-in tolerances and susceptibilities of your vines. Your county extension (255-5522) should be able to help you determine the most effective program in your area for the particular varieties you have. In addition, grapes do best in an area with full sun and good air circulation so anything you can do to improve those conditions is worthwhile.
Q&A Library Searching Tips