Climate Effects on Vine Diseases

The climate has a major effect on vine diseases, and indeed is a major factor determining where grapes are grown worldwide. The most commercially important vine diseases are due to fungi, and these are normally encouraged by warm, humid, and rainy conditions. Such regions as a consequence produce wines of higher resveratrol content, with purported health benefits. Most of the world’s viticulture is therefore carried out in regions with dry summers and less attendant risk of disease, the Mediterranean area being a classic example. However, as the risk of fungal disease decreases, the likelihood of drought increases and, in those parts of Europe where irrigation is prohibited (such as southern France), the effects of drought can be substantial. Some regions such as California, Chile, and Western Australia can be so dry during summer that downy mildew, one of the worst vine fungal diseases, is generally not present.