Last year on a visit to Clos Roche Blanche in the Touraine, proprietor Didier Barrouillet told me about his experiments with planting wild leeks in the vines as an agent against esca, one of the most serious vineyard diseases facing France at the moment. Esca is a fungal disease that attacks the woody portions of the vine—sometimes it will kill the vine slowly, taking several years, but in esca’s most pernicious form the vine simply ceases production and dies within 12 months. Vines that are infected need to be uprooted and burned, and care must be taken to isolate them from contact with any other vines or vine material.
On another visit to Clos Roche Blanche this week, we talked about leeks some more. Up until now, sodium arsenite has been the only treatment against esca, but it’s so toxic that it was actually banned in 2001 as a carcinogen, and anyway, the use of such a product would be completely against Didier’s natural philosophies of viticulture. He cultivates a wide variety of plants in his vineyards, and among them are these little ramps, or wild leeks, that have traditionally grown in the area. “In the old days, everyone used to have leeks in their vineyards,” says Didier. “You would find them anywhere vines were grown.” These wild leeks put out an extensive network of micro-rhizomes, tiny tendrils that interact with the roots of the vines and exchange nutrients, and in addition, they appear to neutralize the three types of fungus that are responsible for esca, inhibiting their ability to spread. For the moment Didier is still cautious, noting that esca can retreat and attack again, and it takes time to observe the long-term effect of these leeks. “But so far,” he says, “they seem to be working. As long as they don’t get eaten by the hares, that is.”
Esca is particularly a problem in the southwest of France, but it’s spread around the rest of the country as well, and it’s estimated that five percent of France’s vineyards could currently be affected by the disease. Champagne is no exception, and it’s becoming increasingly more common when walking around in the vineyards to see the occasional dead vine here and there. Last year, Nicolas Chiquet of Champagne Gaston Chiquet even showed me an entire block of vines in Hautvillers that needed to be pulled out and burned. I haven’t yet seen anyone planting leeks, but as more and more Champenois are moving towards an increasingly diverse array of cover crops in their vineyards, maybe someone ought to give it a try. Historically, vineyards have been part of a complex system of polyculture, and it wasn’t until after the Second World War that vines began to be grown in complete isolation from other plant and animal life. One wonders what has been lost in the process.