bunch rots or berry rots, occur in vines all over the world and can be caused by many species of fungi including yeasts and bacteria. Yield losses can be as high as 80% and wine made from rotten fruit often smells and tastes tainted, typically mouldy, with a perceptible loss of fruit flavour. Vineyards badly infected with bunch rots themselves have a distinctive and unpleasant smell. Wet weather at harvest causes the worst cases of bunch rot, especially if grape skins are broken. The best known of the bunch rots is botrytis bunch rot.