Botrytis bunch rot infection can reduce both yield and quality of grapes in all grape growing regions of Canada. It produces the enzyme laccase which negatively affects the colour, taste and aroma of wine. Grape cultivars with thin skin, tight clusters, or dense canopies are more susceptible to Botrytis. Vineyards become infected early in the season, however visual symptoms on berries do not occur until veraison through to harvest. Berries are covered by a rot and in severe cases whole clusters can become rotted, or drop prematurely.