Botrytis cinerea ("botrytis" from Ancient Greek botrys (??????) meaning "grapes"[1] plus the Neolatin suffix -itis for disease) is a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes. In viticulture, it is commonly known as botrytis bunch rot; in horticulture, it is usually called grey mould or gray mold.

The fungus gives rise to two different kinds of infections on grapes. 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 dessert wines, such as Sauternes or the Aszú of Tokaji/Gras? de Cotnari. The species name Botrytis cinerea is derived from the Latin for "grapes like ashes"; although poetic, the "grapes" refers to the bunching of the fungal spores on their conidiophores, and "ashes" just refers to the greyish colour of the spores en masse. The fungus is usually referred to by its anamorph (asexual form) name, because the sexual phase is rarely observed. The teleomorph (sexual form) is an ascomycete, Botryotinia fuckeliana, also known as Botryotinia cinerea (see taxonomy box).

https://en.wikipedia.org/wiki/Botrytis_cinerea