Of the numerous diseases that attack vines, two fungal diseases are of outstanding importance: vine downy mildew and powdery mildew. Both are natives of the USA. Vine powdery mildew, which lives on both the leaves and fruit, crossed the Atlantic in 1845 (the same year as potato blight) when it was first recognized in England. It reached France in 1848 and then spread steadily through Europe. It is now found wherever grapes are grown. Vine downy mildew reached France in 1878 on rootstock imported from America because of its aphid resistant qualities (the destructive aphid, Phylloxera, had also been introduced from North America) and soon reached epidemic proportions. The disease is of particular importance in the more humid regions such as France, Italy and parts of Spain, but negligible in the drier climates of California. The most important vine disease in the USA is black rot; it is estimated to cause losses of about 20% in the south, and up to 10% in the north.