Which fungus causes gray mold disease on grapes and many other plants?

Which fungus causes gray mold disease on grapes and many other plants? Botrytis cinerea is the principal cause of gray mold.

Botrytis cinerea is a necrotrophic fungus, meaning it feeds on dead or dying plant tissue while helping create that tissue through infection. It affects grapes, strawberries, tomatoes, flowers, and many other crops. On susceptible plants it produces soft, water-soaked decay and conspicuous gray masses of asexual spores called conidia.

On grapes, the disease is often called botrytis bunch rot or gray rot. Persistently wet, humid weather can destroy grape clusters and cause major vineyard losses. Under a different sequence of conditions—wet weather followed by drier conditions—the same fungus can cause “noble rot,” concentrating sugars and flavors in grapes used for sweet wines such as Sauternes and Tokaji.

The species name refers to an ash-gray appearance and clustered spores. Botrytis is also a frequent source of confusion because its effects are not always purely harmful: ordinary gray rot damages crops, while carefully managed noble rot is prized in winemaking. Infection often begins through wounds caused by insects, wind, or physical damage.