A search on the subject will give you the information needed. However, also include the following in your search...grape black rot disease + cornmeal. There are reports that cornmeal spread on the ground around grapes every two weeks does control the situation. Although I have run numerous cornmeal/fungus experiments I have not tested it on grapes and can only suggest you read the experiences of others.

Thanks, I had done a search, everything I found was preventative. Was hoping to find a way to eliminate an infection once it has started. So far neem oil seems to be doing a decent job of controlling the spread. I will definitely look into the cornmeal angle.