'En attendant, l'esca fait des ravages. Tout particulièrement cette année, où la maladie s'est développée à la faveur de longues périodes de sécheresse. « Auparavant, on avait 2 à 5 % de mortalité. Là, on dépasse les 10 % pour les cépages sauvignon notamment. C'est devenue une préoccupation majeure », témoigne Serge Bonnigal, vigneron à Limeray.' (From La Nouvelle République 20.9.2010. Read the rest here.
These are apparently not new vine diseases. Until 2001 they were kept in check by using sodium arsenite. However, its use has been banned because it is a dangerous chemical and can leave residues. To date there is no alternative treatment, although Didier Barouillet (Clos Roche Blanche, AC Touraine) suggests that vines that have always been cultivated organically show a lower incidence of the disease and that the planting of wild leeks can help the vine to resist and even overcome esca,
In Touraine, Sauvignon Blanc is particularly prone to the ravages of Esca. This, of course, is the sole variety that will be permitted for AC Touraine if the reforms go ahead. A true stroke of genius by those responsible!
Furthermore Hervé Lalau reports on his Chroniques Vineuses that the UK's passion for Sauvignon Blanc may be abating. See here.
I suspect that the impetus behind making Sauvignon Blanc, the only permitted variety for AC Touraine, is to avoid having to use the name of the grape variety on the label. I will be amazed if AC Touraine will ever be sold in the UK without Sauvignon Blanc appearing somewhere on the label. Almost all Bourgogne Rouge sold in the UK mentions Pinot Noir somewhere on the label and Chardonnay for Bourgogne Blanc. I cannot see why Touraine Sauvignon will be any different.