January 4, 2013 7:41 pm

The great vine decline

The rise in the incidence of vine wood diseases is worrying vignerons
Illustration depicting wine disease©Ingram Pinn

Throughout my recent travels tasting the 2011s in Burgundy and the Rhône valley, I encountered worried vignerons. This was not the well-ventilated problem of 2012’s demanding growing season and short crop, but something potentially much more serious and long term.

It was my very first stop in the Côte de Nuits, in the well-kept cellars of Denis Bachelet in Gevrey-Chambertin, that first alerted me. Bachelet is a mild man who makes delightfully balanced wines and is not given to exaggeration. But he is worried about the health of his vines, and, in particular, the fact that they seem to be dying off at a rate of between 10 per cent and 20 per cent a year because of esca, a disease that affects the wood of the vine.

Up the road in the world-famous cellars of Domaine Armand Rousseau, Eric Rousseau told me how their revered Pinot Noir vines are dying too. A significant proportion of their 50-year-old Cazetiers Premier Cru vines are now having to be replaced each year, for example. In Châteauneuf-du-Pape, Paul-Vincent Avril’s treasured Clos des Papes vineyards have also been losing about 100 vines per hectare each year to disease. And the worst of it is that there is no known cure.

All that is known is that, most unfortunately, esca has so far been much more likely to affect old vines - those at least 10 years old - than young ones. I say unfortunately because the quality of wine made from old vines well-acclimatised to local conditions with their deep root systems and relatively low yields, is famously better and more complex than the typical produce of young vines – which is why so many labels proclaim Old Vines, Vieilles Vignes or Viñas Viejas.

But esca is increasingly seen on young vines too, and is associated with a substance known as “black goo”. Both wood and leaves can develop patterns of discolouration, generally stripes or spots. Leaves, then stems, may suddenly shrivel in the middle of the growing season, the bunches of grapes fall to the ground and the vine suffers apoplexy, or sudden death. It’s impossible to predict how soon a vine will die after the first symptoms appear, but it can happen in a matter of days, particularly in midsummer in dry weather after a period of wet weather.

Vieilles Vignes 2007 Gevrey-Chambertin

This gorgeous Vieilles Vignes 2007 Gevrey-Chambertin from Denis Bachelet (£42 Berry Bros) was made from 75-year-old vines. How many have survived the past five years?

Then there are at least two more nasty conditions that are currently preoccupying The International Council on Grapevine Trunk Diseases (formed in 1999): eutypa dieback, also known as eutypiose, and a newer one on the scene known as botryosphaeria dieback, black dead arm or BDA. All of them have been much more evident recently, particularly last year. One theory put forward in a paper on the increased incidence of esca and BDA, published by the Institut Français de la Vigne et du Vin last September, is that the unusually wet spring of 2012 followed by unusually high temperatures in early summer may have stressed the vines and left them particularly vulnerable – with some vineyards suffering losses of up to 50 per cent of vines.

It has been known since the beginning of this century that both Sauvignon Blanc and Cabernet Sauvignon, the much admired vine variety and the noblest grape of the Médoc in Bordeaux, are particularly susceptible to all three of these maladies. What is worrying is that they seem to be spreading to varieties such as the Pinot Noir of Burgundy that were not previously thought to be especially prone.

Despite considerable monitoring and identification of various associated fungi, very little is known about exactly how and why the disease spreads. Until the beginning of this century vines used to be treated with arsenic but, for obvious reasons, this is now banned – which may have played a part in the rise in incidence of these vine wood diseases. And they are by no means limited to France. They are now common in Italy and seem to have swept their way through Spain from north to south – and are now so familiar that some Spanish vintners have evolved a folkloric way of dealing with them. Vine trunks are rent asunder, the two halves wedged apart with a big stone to encourage the offending fungi to dry out, and the next year’s growth taken from a new branch that sprouts below the join. Fingers are then tightly crossed.

The maladies are not (yet?) quite so prevalent in Germany but are becoming more so, as they are in Switzerland where hopes are being pinned on a new pruning technique developed in Italy which may stave off the spread of the relevant fungi. One theory is that it is pruning rather than the fungi themselves that provoke the diseases.

It is all rather horribly reminiscent of the last wave of vine pests and diseases to spread through Europe in the 19th century when powdery and downy mildews were followed by the most deadly of all, the phylloxera louse, fatal to European vines. At one point it looked as though the whole of French wine production was doomed, until it was realised that American vine species are resistant to phylloxera, since which time most European vines, and the members of European species that produce 97 per cent of all wine made today throughout the world, have been grafted on to phylloxera-resistant American roots.

Mickaël Anneraud, director of the Médoc subsidiary of the local Chamber of Agriculture, has a theory that the characteristics of rootstocks may hold the key. He has noticed that even in contiguous plots in his much-affected wine region, vines that are 25-40 years old have been more robust than those that are around 20 years old, planted when the rootstocks commonly used were markedly less vigorous. He thinks it may be worth researching a possible link with vine vigour (how leafy the vines tend to be).

The Burgundians, on the other hand, feel bereft since they have no equivalent of the vast, well-funded, wine-minded University of Bordeaux. One theory is that the nurseries have been cutting corners when sanitising the young cuttings they sell, a worrying echo of what happened to the quality of wine corks a decade or so ago.

www.jancisrobinson.com

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