Esca

Esca is a fungal disease that is hitting the Loire Valley vineyards hard. Many winemakers have lost thousands of vines over the past few years. There is no currently available effective treatment for the vines once they have the disease and it has the potential to turn into a crisis of Phylloxera scale proportions (when at the end of the 19th century a root aphid which introduced a fungal disease nearly wiped out the French wine industry).

Part of the problem is that the disease is actually caused by a group of closely related fungi. The only treatment that kills them, sodium arsenite, is a known carcinogen and so toxic to all living things it is too hazardous to use and has been banned. At present it isn't even sure how the fungi are transmitted -- whether they are soil, water or air borne. However their means of transport, they enter the plant at the level of the graft, and affect the root stock. The vine reacts by blocking off its vascular system, but the fungi propogate rapidly and very quickly the plant kills itself by blocking so many of its sap runs that it starves. Typically the leaves turn yellow with a characteristic pattern.

Removal of affected 35 year old vines in Vouvray. The remains were burnt, but these vines were only middle aged, so it is a blow to have to replace them. Photo courtesy of Chateau Gaudrelle.

The French National Agronomy Research Institute (INRA) is working on finding a solution, and has clarified what the symptoms are and identified the specific organisms concerned, but a cure is proving elusive. At the moment, it seems that inoculation of root stock with the oomycete Pythium oligandrum may have promise. This organism is a parasite of many harmful fungi as well other undesirables such as Botrytis and Phytopthora. It not only directly parasitises the fungi but causes the vines to react by stimulating healthy growth and chemicals to defend against pathogens.

New certified clean plants ready to restock the vineyard. Photo courtesy of Chateau Gaudrelle.

In the meantime, winemakers are turning to all sorts of alternatives. Some are planting wild leeks amongst the vines, in the belief that their associated mycorhiza can combat the esca. Others are 'playing music' to the vines, using devices which send out periodic audible tone patterns which the inventors claim disrupt the proteins of the esca fungi and prevent them from growing.

Charles and I discuss the Genodique 'music box' in the cellars of Chateau Gaudrelle before it goes out into the vineyard. I am extreeeeeeeemely sceptical...

My reading suggests that soil conditions play a part, and parcels with residual herbicides or vines that have had their soil microbia disrupted are particularly at risk. Another risk factor that most people agree on is when a warm wet spring is followed by a dry summer. This type of weather pattern always seems to cause a serious outbreak of esca. Once the disease is detected in a parcel of vines, those vines and their infrastructure are removed and new vines from a nursery that can be trusted to supply clean stock are replanted. The disease can take hold and kill very rapidly (within months) or the vines can linger on for several years with symptoms including yellowing leaves and slow maturing grapes.

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Fête Nationale: Simon went to the celebrations in Preuilly, held on Saturday night, and really enjoyed himself so he made a video. There were fire eating zulu drummers, loud, generous and colourful feu d'artifice and the traditional bal populaire, at which the Madison was danced to Just a Gigolo well into the night. And in case you are wondering, only anglos refer to Bastille Day, and lots of communes hold their 14 juillet Fête nationale celebrations on the eve.

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A la cuisine hier: The sour cherry syrup has now infused sufficiently, so was strained and bottled, yielding 2 litres for adding to fizzy water, or perhaps instead of cassis for various kir style drinks. The sour cherries macerating in sugar were also ready to have a bottle of cheap vodka tipped over them. They will sit in unsealed jars somewhere reasonably warm for a month to 'brew'. My friend Christine told me that in the old days they were sat out in the sun, although she has also been told by an old lady that the proper way to do it is to put them out in the moonlight.

I picked 5.5 kg of sweet yellow cherries from the enormous tree on our orchard neighbours' plot. We ran into her the other day on the way to the pool and she suggested I help myself, although warned me that they were full of asticots (maggots). It's true that some of the fruit had the tell tale shadow under the translucent skin that indicates it is infested with cherry fruit fly. However, most of them are pretty well perfect. I've set aside some to eat fresh and Simon has make an Asian sauce (basically plum sauce but made with yellow cherries instead of yellow plums). I'll take a small jar around to her in a few days. Even if she doesn't cook Chinese food, it will go well with cheese.

Yellow cherries aren't grown commercially, but they are widely grown in gardens here. The theory is that the birds don't notice they are ripe and ignore them. I don't know what variety this one is. It turns butter yellow when ripe. Our yellow cherries are Coeur de Pigeon and Napoléon, both of which get a rosy blush when ripe, so the birds aren't fooled at all. They also ripen much earlier and it seems to me that this is the real key. Birds get an awful lot of early and mid-season cherries, but leave the late ones. I think they've got tired of cherries and have moved on to something else.

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Orchard News: A Marbled Fritillary Brenthis daphne spotted laying eggs on our tayberry. Their caterpillars eat brambles, so why not tayberries. This is a new record for the orchard, and somewhat of a surprise. This species seems to be only Fritillary butterfly doing well this year, and I have recorded it for the first time at one of my Chaumussay transects too (where it was not a surprise, but I just hadn't ever seen it there before).

Vines with Esca

On a recent visit to a parcel of vines in Rochecorbon (Vouvray appellation) we had a discussion about the fungal disease esca. It's causing real headaches for the wine industry and we were able to take photos of affected vines and learn about how it is managed.

The characteristic pattern that develops on the leaves of affected vines.

I was impressed at how open the winemakers are about whether they have the disease and how much of it they have. It's the sort of thing that many industries would be very secretive about, just in case it damaged consumer perceptions. However, diseased vines sometimes limp along producing quite useable grapes for years before succumbing, so I guess the winemakers feel there is nothing to hide, and much to be gained by educating the public about what a serious threat it is. Plus, virtually every vineyard is affected.

In the parcels of Chenin Blanc we looked at I would say there is currently one or two vines in every row with the disease. I was surprised to learn that they are just left there until 90 - 95% of vines are affected. They can't be treated as there is no known cure (apart from sodium arsenite which is banned because it is so toxic to everything, not just fungal diseases...). Once the whole parcel is diseased the vines are grubbed out, burned, and fresh certified disease free stock planted. The vines here are being subjected to an outlandish sounding alternative treatment involving sound patterns and the affected plants are counted on an annual basis to see at what rate the disease is spreading.

A diseased vine.

It is not cost effective to replace vines one by one as they become infected, and I suspect it becomes difficult to manage a parcel with grapes of many different ages. It is much easier to harvest grapes from a parcel that is all the same age. I was particularly surprised that infected vines are not grubbed out immediately in an attempt to prevent the spread of the disease though. I was also surprised that the soil is not usually left fallow for a significant period after the diseased vines are pulled out. In most cases the new vines are planted within weeks of the old ones being removed. Possibly these measures are not seen as necessary because no one knows how the disease transfers from one plant to another, so it may be a pointless use of time.

For my previous post about esca, which goes into detail about the effect the disease has on the vines, see here.

Fungicides in the Vineyard

At the Chateau Gaudrelle estate in Vouvray AOC they have several parcels of vines. They never blend the parcels used for making still wines, but the sparkling wines are a blend of 7 different parcels.

The vineyards of Vouvray sit above the Loire river on its right (north) bank just east of Tours. The Loire sucks a trail of cool damp weather into the area and the closer to the river the vines are the better they do. A convection current rolls the air over the vines in the vicinity.

Guillaume, the vineyard master, and an assistant work amongst the vines.

The soil they grow in is flinty clay and it produces an intensely fruity grape. The vines are carefully pruned for their role in producing high quality bunches of wine grapes. The winemaker, Alexandre Monmousseau, is not aiming for good looking vines, but ones that produce the best grapes. The chenin blanc grape variety grown here is quite robust and doesn't mind a bit of scorching. The vines are totally at the mercy of the weather -- no covering against hail or frost is allowed, no irrigation in times of drought. As a result, each vintage has a unique signature.

A session in the vineyard itself, as opposed to the winery and tasting room, is always educational, and a recent visit was no exception. Alexandre started talking about fungal diseases and how to combat them. I really pricked up my ears when he said they were no longer using copper sulphate (bordeaux mixture). 

This 19th century concoction is widely used and available to both professionals and home gardeners. Its use is currently allowed in organic agriculture. However, it is highly toxic, especially to mammals (that's including us humans...), let alone fungi, and is the sort of product that makes a complete joke of organic practices. As Alexandre eloquently put it, in the 19th century the contents of two South American copper mines were dumped on the vineyards of France, and all that copper is still there! It lowers soil biodiversity and he says it means the soil is like a run down battery, struggling and overloaded. The sulphur component of most fungicides (modern and old) makes them problematic to apply too. They are toxic to insects, and in powder form, not good for the vine workers.

He switched several years ago to the much less well known phosphonate fungicides, developed in the 1970s. The active ingredient is potassium phosphite and the product has a low copper content, and (I think) no sulphur. The mixture is sprayed on to the vines in much the same way as copper sulphate but has the advantage of being longer lasting because it is to some extent absorbed by the plant. Copper sulphate simply sits on the surface and washes off into the soil (to kill more soil bacteria...) as soon as it rains and must be repeatedly applied. The potassium phosphite acts a bit like a systemic, lodging itself in certain parts of the plant. It doesn't completely eradicate fungal diseases like powdery mildew, its main target, but the soil bacteria will 'mop up' the remaining spores and residual fungus. Potassium phosphite breaks down into hydrogen, oxygen and potassium and is completely harmless in the soil (even mildly beneficial).

Lining up to mow down a row in the vineyard.

Despite its benefits, potassium phosphite must still be applied before an outbreak of fungus occurs in order to be effective. Good winemakers watch the weather carefully and apply when weather conditions suggest an outbreak of mildew is imminent (warm and wet). Lazy vineyard managers simply use the calendar and apply a fungicide every 2 weeks during the summer. (Another winemaker we visit, who uses modern synthetic  pesticides said during the wet summer of 2012 he sprayed 9 times. His organic neighbour sprayed 18 times, with copper sulphate...)

A mildew outbreak is not the only fungal disease that the local winemakers dread. Esca is also a killer, and much more difficult to control. The only certain treatment is arsenic based, which of course is banned. Esca is a combined systemic attack on the vines by three related fungi. The cost of replacing affected vines is significant. From grubbing up to waiting 5 years for a legally productive vine, each plant costs the winery €10. At Chateau Gaudrelle they have resorted to using an unproven and unusual technique to combat the disease. Here they play a specifically designed musical sequence to the vines several times a day, which the inventors of the system claim will modify the amino acid production in the fungi and disrupt its lifecycle.

The same people are working on a similar system to control powdery mildew. Alexandre has been trialling the system for esca for several years now and I think is increasingly convinced of its efficacy. I hope it does work, but we shall see...

A few weeks after this visit Charles, who works at Chateau Gaudrelle, bounced out when we arrived, to tell us they had spent the morning in the vineyard, winding tendrils into the wire trainers. Normally these are given a 'haircut' to reduce growth, make the vine concentrate on its fruit and prevent the vine creating too much shade. However they are trialling a new system for managing the tendrils, having read a study which suggests that the vines use their tendrils like antennae to measure the surrounding conditions and respond to them. Chop them off and the vine loses that ability, so in order to allow the vine to keep them, but prevent them whipping vine workers in the face like triffids, Charles and his colleagues had been sending them horizontal. The theory is that the tendrils will at some natural point stop growing. They will be watching with interest to see how this management technique works in practice.

Alexandre ferrets around in the vineyard soil to find pieces of flint and fossils to show visitors. (Note that this parcel is still in recovery from decades of pesticides and herbicides applied by the previous owners, so the soil is still rather bare under the vines.)

Another vineyard management technique they use is mowing between the rows. The grass is left under the vines to provide a bit of mulch. Many winemakers still use herbicides to create bare earth under the vines, but this is increasingly criticised, and certainly leads to problems like erosion on sloping sites. Those who advocate allowing grass and wildflowers under the vines point out that it creates a cool moist microclimate around the base of the vines and means they have to compete for nutrients. Vines which have to send their roots deep to survive generally produce the best grapes for wine.

Chateau du Petit Thouars

The Chateau du Petit Thouars is the sort of place we have wanted to take clients for ages but somehow or another it never worked out. Finally, at the beginning of June, we had clients who wanted to visit the Chateau of Azay le Rideau, a goat cheese producer and taste some red wine. Because the goat cheese producer we were going to was Le Vazereau, near Chinon, I immediately thought of Petit Thouars for the wine.

The chateau is genuinely a family home, as well as offering holiday accommodation. It is run by Sébastien du Petit Thouars and his Canadian wife D'Arcy. Their winemaker came from one of the most famous estates in the area, and they have 16 hectares of chenin blanc and cabernet franc vines. Sébastien's father, the Comte du Petit Thouars is the former director of Baccarat Crystal and his mother was a wine journalist. It is really they who revived the life of the chateau as a vineyard when they inherited the property in the 1970s. Sébastien and D'Arcy left their careers in Paris and came down to enter the family business from 2008.

The 17th century chateau du Petit Thouars.

I thought D'Arcy provided one of the best tours of the vines and winemaking facility that we have experienced. She was very knowledgeable about how the grapes are cultivated and the various problems and environmental conditions that must be dealt with as part of the seasonal cycle. For example, she thought to mention that it is not permitted to irrigate vines in France, which French winemakers always forget is a revelation to American and Australian visitors. 

The vines look out over the Vienne river down in the valley, and across to the nuclear power station with its dramatic plumes of steam. Sébastien sits on the board of local winemakers and is doing his best to influence the AOC to allow new and better practices. He was instrumental in their area being granted Chinon AOC status rather than having to label their wines as merely Touraine. His argument is that they are a long way from the nearest other Touraine wineries and had little in common with them. It was absurd that they could see Chinon wineries from their vines, but not be allowed to label their wines with the higher status appellation.

He is also arguing that a different pruning method known as Poussard which appears to help against the fungal disease esca should be allowed. At present, the AOC is discreetly turning a blind eye to those who use the new technique, but it really needs to be enshrined in the regulations to allow everyone to feel comfortable and to manage the vines sensibly. Their vineyard is in the very early stages of converting to organic, a process their winemaker is not entirely convinced by, so they are taking it slowly and gently. But, as D'Arcy pointed out, they have two small children. Of course they don't want to be exposing them to agricultural chemicals unnecessarily.

Our clients posing in front of the chateau with Sébastien.

D'Arcy had to head off to town after our vineyard tour, but Sébastien took the tasting with our clients. He took us through a series of reds from different years which was an excellent exercise in terroir. Hint: their 2015 red is very good and developing into quite a complex wine. I personally liked the 2014, because it was a bit lighter on the tannins and I'm not a huge fan of tannins. I thought the chenin blanc was good too, especially in comparison to other Chinon AOC chenins I have had (Vouvray is really the heartland of this grape and it often feels like a bit of an after thought in Chinon).

Both Sébastien and D'Arcy were charming, skilfully blending candid personal details of their lives running this small beautiful estate with a professional level of marketing and business savvy. I hope we get the opportunity to visit them again.

D'Arcy (right) with one of our clients in the vineyard.

Visiting the Vines in Vouvray

Charles Morand from Chateau Gaudrelle rang me recently to tell me that they had been approached by a journalist who wanted to interview them and some visiting American tourists at the winery. He thought we might be interested in 'supplying' the American tourists. We were happy to suggest some suitable dates for the meeting and asked our clients if they would be willing to be involved. Charles and I finalised our arrangements and then we waited for the journalist to confirm. In the end the journalist didn't turn up, but we went ahead with the visit as planned without them.

Charles talking about the vines to me and one of our clients.

It included not just visiting their winery caves on the Quai de la Loire as we usually do but also going up on to the top of Rochecorbon and seeing the vines too. Charles took us to an area called Montgouverne, where Chateau Gaudrelle owns about 2.5 ha of vines. They purchased these two parcels about 2 years ago and are converting them to a near organic form of management known as agriculture raisonnée ('intelligent agriculture'). The former owner practiced a full-on 'nuke all the pests, diseases and weeds before they even make an appearance' approach, so the vineyard isn't yet in the condition they would like it to be (for example, very little grass grows between the rows yet). They've decided not to go completely certified organic because they feel that it could result in them losing the crop if the weather was particularly poor. They manage the parcels in ways that reduce the risk of fungal diseases and pests, and are aiming to increase the biodiversity, especially insects and wildflowers. However, they want to retain the option of being able to use fungicides to save the grapes if absolutely necessary, but they do not use pesticides routinely.

 Youngish vines on flint clay soil.

Charles showed us the two different types of soil in the parcels, how to tell the age of the vines and what variety they were. We also discussed the problem of the fungal disease esca and how the grapes were picked.

Rochecorbon is in the Vouvray wine appellation, so only chenin blanc grapes are grown. They have to be planted in rows 120 cm apart and the number of plants must not exceed the density per hectare specified by the authorities. They are also not allowed to produce more juice than the appellation rules specify.

 Claudette on her second proper job, lurking about in the vineyard.

The vines are 15 years old in one parcel and 35 years old in the other. That makes them fairly young and middle aged respectively. Chenin blanc grapes don't produce a useable harvest until they are 5 years old and the grapes produced by very young vines are just left on the plants to be consumed by birds. Deer are apparently not a problem. We saw their tracks but Charles says although they might nibble a few grape berries it's nothing that warrants the vineyard being protected from them.

Most of the grapes are picked by machine. It goes along the rows, gently shaking the bushes. It is calibrated to shake with just enough force to make only ripe grapes of a certain weight fall off into collecting baskets. These grapes will go to making the dry and semi-dry wines (including the base wine for the sparkling Vouvray). At the end of the harvest, if weather conditions have been favourable, hand pickers will go through and selectively pick grapes from certain parcels for making sweet wine. This is a practice known as passerillage where the grapes are allowed to dry to currants on the vines before being picked. The last time Chateau Gaudrelle was able to make sweet wines was 2010, so everyone is hoping for fine weather and a continental (east) wind in mid-October to replenish the stocks.

Middle aged vines on limestone clay soil, full of fossils of marine creatures from 90 million years ago and only a few metres away from the flinty soil in the photo above.

We sampled the grapes, but they were still not quite ripe on 25 September. The harvest is scheduled for between 10 and 20 October -- the latest ever due to winter hanging on until June this year. Although Chateau Gaudrelle lost 60% of their crop on 17 June due to a hail storm, September was looking very promising for maturing the grapes, with very warm and mostly dry weather. The day we visited the vines were starting to brown at the tips, indicating they needed a bit of water. Worryingly, they got more than a bit only a couple of days later, with the weather deteriorating from warm and a bit humid to a day of heavy rain followed by several warm drizzly days. This is just the sort of weather the winemakers don't want at this time as it promotes fungal diseases and rot.

Update: Simon, who took these photos, tells me I had the soil types back to front so the photo captions have been corrected now.

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Orchard News:  I picked the last of the Reine de Canada apples and gathered some more hazel nuts. Actually, the hazels appear to be filberts according to information provided by Pauline. I've got enough now, so the rest can go to nourishing various foraging small mammals (squirrels, voles and the like). I'll continue picking a punnet of grapes every day or so for the next couple of weeks. 

One of the apples weighed 350g (average apple weight is half that). Its friend next to it on the tree attempted to break my nose by leaping off and landing smack in the middle of my face from a great height.

The harvest mites (aoûtats in French) are driving me mad. I never see these microscopic creatures, but they bite, leaving me with itchy red welts around the line of my bra and underpants and in the crook of my elbows. Thank goodness for Onctose cream, with its antihistamine and local anaesthetic.

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A la cuisine hier: A veritable tomato led frenzy, with Simon making 12 jars of pasta sauce and me whizzing up a dozen little pots of Ken's salsa for the freezer. I also cooked up some quinces which are currently suspended in the jelly bag.