I would wear long old clothes, gloves, mask, gloves..............that is a fungus.................gets little spores.................so if you are going to eat those grapes..............I would wash them by using a little vinegar and water and soak & rinse before taking them inside in the fall when the leaves fall off you can spray it with a fungicide....read the label first...wear same kind of clothing plus a mask when spraying.........do it again in the spring......make sure that grapes are on the label list of plants covered there are 6 different spray that are on the internet........some must be available at your lawn & garden section.