Share This Article
Many American winegrowers have decided to plant hybrid grape varieties that are better able to combat the effects of global warming.
Every year, many American winegrowers make the same observation: the climate is not only becoming more unstable but, above all, it is changing. In California, for example, average temperatures are higher, while droughts are becoming common. These characteristics are putting a strain on the vines, forcing growers to make greater use of irrigation, with a significant impact on already low water reserves.
In the Hudson Valley, the temperature is also rising, increasing the humidity in the air. These conditions are ideal for the development of certain mould species – including mildew – and favour the proliferation of invasive insects, in particular the lycorma delicatula – an insect originating from South-East Asia that has invaded the North American continent. Winegrowers are therefore forced to multiply the application of fungicides and insecticides, with consequences that are both economic and, above all, environmental.
Cross-breeding and hybridisation
To combat the effects of global warming, several winegrowers have turned to hybrid vine species, which they hope will be more resistant to new climatic stresses. Members of the Heritage Wine Project have developed a range of vines based on crosses between native species and European varieties. The former, which are hardier and better adapted to their terroir, strengthen the plant’s resistance to attacks. The latter contribute their superior organoleptic properties, producing wines very close to the standards sought by North American customers.
As far as indigenous species are concerned, the American winegrowers of the Heritage wine project favour in particular labrusca, aestivalis, rupestris, and riparia. They have the advantage of having evolved in the same environment as the diseases and moulds that are proliferating today due to global warming. Some of them had already been used to save certain European grape varieties after the terrible phylloxera epidemic, which ravaged European vineyards in the second half of the 19th century. Rootstocks from American plants, naturally immune to phylloxera, were used.
Another avenue explored by some wine professionals is to rediscover forgotten hybrid varieties. These are either the result of natural cross breeding or of manipulations carried out in the 18th and 19th centuries by European settlers. These varieties, which are perfectly adapted to the terroir and better able to cope with the effects of global warming, are historical grape varieties that do not grow anywhere else. The downside is that, like most old or semi-wild varieties, they mature later – usually after five years – and, above all, their yield is lower.