Recovery after curettage of grapevines with esca leaf symptoms

Grapevine curettage was re-introduced in France in the early 2000s, and is important for facilitating recovery of plants from esca disease. This surgical practice involves removal of deadwood of vines with leaf symptoms, focusing on white rot generally observed at the centres of grapevine trunks. Assessment of the efficacy of this practice was initiated in the Bordeaux region in 2014. One ‘Sauvignon Blanc’ vineyard severely affected by esca was initially surveyed in the summer of 2014, to identify and treat vines with esca foliar symptoms. Annually thereafter, from 2014 to 2018, selected vine stocks were curetted. Two other ‘Sauvignon Blanc’ vineyards also displaying high levels of esca damage were added to the study in 2015 and 2016. Curettage treatments ceased in 2018, resulting in 11 trials (vineyard × year combinations). In total, 856 vines (422 curetted and 434 control vines) were then surveyed annually up to 2021, for assessments and comparisons of esca development. At each site, plants with esca symptoms recovered well after curettage : on average 85% of all curetted vines became asymptomatic the year immediately after the treatment. Six years after treatment, for curettage campaigns carried out in 2014 and 2015, more than half of the curetted vines were symptom-free, whereas <12% of the control vines were asymptomatic, and gradual loss of efficacy was observed at each site. The mean annual proportion of efficacy erosion was approx. 8% per year. This study highlights the possible short- and midterm benefits of trunk surgery to enable recovery of esca-affected vines, and for them to recover and remain leaf-asymptomatic for several years

Le millésime 2017 à Bordeaux

Article dans une revue professionnell

Le millésime 2018 à Bordeaux

Article dans une revue professionnell

ScanPEP un nouvel outil d’evaluation de la maturité des pépins.

Article dans une revue professionnell

J. agric. food chem.

Phenolic compounds are among the most important quality factors of wines. They contribute to the organoleptic characteristics of wine such as color, astringency, and bitterness. Although tannins found in wine can come from microbial and oak sources, the main sources of polyphenols are grape skins and seeds. Since the 1960s, this subject has been widely studied by a large number of researchers covering different types of wine, climate conditions, growing practices, and grape varieties. As these works have been conducted under different conditions, the data collected can be conflicting. Moreover, even though the biosynthesis of the major proanthocyanidins units (+)-catechin and (-)-epicatechin is well-known, the mechanism of their polymerization remains unexplained. This is why the question remains: what factors influence the biosynthesis, the quantity, and the distribution of tannins in grape seeds and how can winemaking processes impact the extractability of seed tannins in wine

Vigne : pourquoi tailler moins ras aide à freiner l'esca

Article dans une revue professionnelleCONTEXTE - Si la pratique de la taille est fortement documentée, la formation des cônes de dessiccation issus des plaies de taille reste mal connue. Ces zones de bois mort peuvent limiter le fonctionnement physiologique de la souche, donc contribuer aux phénomènes de dépérissement et aux MDB. ÉTUDE - Trois types de plaies de taille ont été testés sur deux cépages en 2014 et 2015. RÉSULTATS - Les résultats montrent qu'en fonction de la sévérité et de la position de la plaie, de la présence d'un nœud et du cépage, la profondeur et la forme du cône de dessiccation peuvent varier. Conserver le diaphragme et limiter les tailles rases sont un premier pas vers une taille moins mutilante et plus respectueuse de la plante

Food chem.

The extraction of seed and skin tannins in wine has been investigated at three different grape maturity stages. For that, the tannins content and composition of seeds and skins at three different maturity stages were characterized. After that, an original approach of nanovinification was conducted. At each maturity stages, three winemaking modalities have been produced: (i) a control modality, (ii) a seed modality made of exclusively with seed and (iii) a skin modality made of exclusively with skins.[br/] The aim of this work is to describe and explain the seed tannins kinetics release in wine but also the impact of grape maturity on seed tannins extractability. For that, the evolution of seed and wine tannins content have been followed during the winemaking, from alcoholic fermentation to post-fermentative maceration

Biostimulation de la vigne, l’action d’un filtrat d’algues. Évaluation et explication des effets du filtrat d’algues (GoActiv) à base d’Ascophyllum nodosum sur la qualité de la vendange.

Article dans une revue professionnelleContexte - Le biostimulant de Goëmar à base d’algues nommé « filtrat d’algues (GoActiv) » utilisé en encadrement de floraison de la vigne a des effets bénéfiques lors de sa période d’application. Mais des effets plus tardifs, jusqu’à la vendange, en particulier sur le taux d’anthocyanes du raisin noir, ont été rapportés. Ce point devait être élucidé. Travail - Une étude a donc été menée dans le Bordelais, sur cépage merlot, par l’université de Bordeaux, durant trois années. Elle a consisté à évaluer les effets du filtrat d’algues jusqu’à la vendange et à élucider leurs mécanismes au niveau de l’expression des gènes impliqués dans la synthèse des composés phénoliques, dont les anthocyanes. Résultats - Une accélération de la synthèse des anthocyanes a été démontrée. Elle facilite le choix de la date de vendange. Par ailleurs, la stimulation de l’expression de deux gènes a été mise en évidence. L’un d’eux intervient au début de la biosynthèse des composés phénoliques au stade bouton floral, le second agit sur la synthèse des anthocyanes à partir de la véraison