Grey rot is a grapevine disease that has accompanied European viticulture for centuries, especially in wet and cool years. It occurs most often on varieties with densely packed grapes (where individual grapes can't breathe as well). Grey mould looks unattractive and can become a nuisance when the infection is out of control. However, it is non-toxic and can be compared to a noble mould on cheese! It is even used in some high-quality wines as "noble rot" and is actually cultivated sometimes just to make sweet dessert wine! Grapevine varieties with loose grapes are rarely attacked because the water drips down and dries off quickly after rain. Infested berries can be rinsed with a strong water jet or the rotted grapes can be sorted out after harvesting; the rest of the grape can then be consumed normally.
(lat.: Botrytis cinerea)