A grey fungus
, Botrytis cinerea
, that affects wine grapes
. It is also called Botrytis bunch rot
. The fungus gives rise to two different kinds of infections. The first, grey rot, is the result of consistently wet or humid conditions, and typically results in the loss of the affected bunches. The second, noble rot
, occurs when drier conditions follow wetter, and can result in distinctive sweet wines.