Grey Mold of Wine Grape

The causal agent is Botrytis cinerea (teleomorph Botryotinia fuckeliana). The pathogen infects inflorescences, causing them to turn brown and abscise, as well as green parts of the vine and rachises, where greenish-brown spots develop, leading to desiccation and yield loss. Under high humidity conditions, a characteristic grey conidial mold develops on the affected tissues.

The most destructive manifestation of the disease occurs on berries, which soften and turn brown. The fungus overwinters as mycelium in the bark of annual shoots, on rachis remnants, and in the form of sclerotia. No specific genes for complete resistance have been identified in Vitis vinifera; breeding programs focus on identifying QTL loci responsible for tolerance and morphological traits such as cluster density and skin thickness.