Written on 21/07/2022
A technique that gets people talking
It's a technique that never ceases to be talked about. Hot water treatment of vines. This technique, which has been around since the 1970s, involves immersing the wood or plants in water at 50°C for 45 minutes to combat a bacterium. The hot-water treatment used on seedlings leaving the nursery is effective against flavescence dorée: all the experiments carried out to date by the Institut Français de la Vigne et du Vin and other partners have never found the phytoplasma - a kind of cell-wall-less 'bacterium' responsible for flavescence dorée - after treatment in previously infected wood.
In Burgundy, it is compulsory to use hot water-treated seedlings for all planting, replanting and transplanting.
But for some years now, it's been the talk of the town. And with good reason: on the one hand, there are those for it, and on the other, those against it. This is particularly true of Jean-Hugues Goisot, president of the technical commission of the Confédération des Appellations et des Vignerons de Bourgogne, who wants to see the technique continue. In a press release, he stated : "Grafting can indeed transmit the phytoplasma responsible for flavescence dorée. However, while it is possible to survey the mother vines of grafted vines for symptoms in vegetation, the rootstocks may be healthy carriers, and will not transmit the disease. So, doubt will always remain... That's why in Burgundy, since 2013, TEC has been made compulsory by prefectoral decree, and is included in the specifications for all appellations. If the region's nurserymen want their plant material to carry the "blue label", they will have to comply."
But according to David Amblevert, President of the French Federation of Wine Nurseries, this technique is not without danger, and he therefore wishes to stop it. According to him, it can lead to"problemsproblems of non-reproduction at planting delays in budburst (up to three weeks on Sauvignon Blanc, according to an observation made in Gironde), extreme sensitivity of certain rootstocks such as 41B, SO4 and Fercal... TEC is certainly a natural treatment, but it pushes the vine to the limit of its physiological resistance. This situation is forcing nurserymen to alert winegrowers requesting TEC, or even to have them sign a waiver, because of the potential economic damage. "
