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The study could not have been conducted without the vinegrowers who allowed data collection and all trainees who initiated the data analysis (Marie Daniele, Tristan Boisson and Anne-Marie Varela).; International audience; Vineyards are an appropriate model for testing the filtering effect of management practices on weed communities, as a wide range of practices (tillage, herbicides and mowing) is implemented. The aim of this study is to highlight which trait values are selected by each practice in different environmental conditions, with special references to Grime's CSR strategies. A combination of a multivariate analysis (RLQ) and the fourth-corner analysis was used to analyse 400 floristic samples belonging to 100 vineyards in the wine-growing region of Bordeaux (France). The main structure of vineyard weed communities was shaped by the opposition between mowing, favouring hemicryptophytes with a competitive strategy, and soil tillage, favouring therophytes and nutrient-demanding species with a ruderal strategy. Secondly, the vineyard weed communities differed according to the trophic status of the soil. Vineyards on acidic, sandy soils with low organic matter were characterised by small-seeded annuals with a stress-tolerant strategy whereas vineyards with clayey, calcareous soils rich in organic matter, harboured larger perennial nitrophilous species with large seeds and a competitive strategy. Our study is the first to show that weed species responded consistently to two independent gradients with specific traits associated with disturbance (life cycle and SLA) and soil resources (plant height and seed mass) gradients. Based on knowledge of the soil characteristics, it becomes possible to predict which type of weeds will develop according to the combination of practices applied on the vineyard rows and inter-rows.

International audience; Botrytis bunch rot (BBR) is a major fungal disease of grapevine worldwide caused by Botrytis cinerea. The pathogen presents a complex life cycle in the vineyard with a great genetic variability, multiple biological forms and various infection pathways highly dependent on meteorological conditions. Losses at harvest can be very important quantitatively as well as qualitatively by modifying wine quality from 5% of rotted berries upwards.Extensive research on BBR epidemiology has been carried out at INRA Bordeaux-Aquitaine evaluating and developing disease risk indicators. An interesting case of study is the B. cinerea floral calyptras infection rate as a potential early indicator of disease development and losses at harvest. From 2011 to 2015, B. cinerea infection of calyptras from an experimental Bordeaux vineyard (cv. Merlot) was evaluated at the end of flowering. The potential relationships between the infection on calyptras and the climatic conditions are analysed and discussed. However, no significant correlation was observed between the indicator and BBR disease incidence or severity.Additionally, alternative strategies to chemical fungicides have been evaluated in different Bordeaux organic vineyards in 2015. Natural products, already commercialized for their use in organic viticulture, were applied at key phenological stages or following a disease risk index. Results indicated the reduced interest of a wicker tea product, whereas potassium bicarbonate, kaolin and a fatty acid products showed BBR reduction and may be good candidates as alternative strategies for BBR control.

In the Gironde département (French administrative entity) situated in the Bordeaux Region, about 6 millions of hectoliters of wine are produced each year on 120,000 hectares. This production generates important quantities of winery effluents which part is still untreated. The Chambre d'Agriculture (Chamber of agriculture) of Gironde has undergone, with the support of the local Water Board (Agence de l'Eau Adour-Garonne) and of the Conseil Général de Gironde (council at département level), a study aiming at evaluating the importance of the untreated winery effluents and at assessing the most sensitive zones where actions should be taken as a priority. In Gironde, 28 % of the wineries have set up a solution for wastewater treatment and 57 % of the total volume of winery effluents is treated. All the cooperative wineries have a wastewater treatment system. The rate of equipment of the smallest wineries is the lower and only 16 % of the wineries producing less than 500 hl/year treat their effluents. The areas with the highest percentage of treated effluents are those where collective solutions have been set up. These shared facilities are now playing an important part in the treatment of winery effluents and half of the equipped wineries are member of a collective structure such as a CUMA (Cooperative for the use of agricultural equipment) or a GIE (Economic interest group). Furthermore, at the scale of the catchment area, 3 zones with high quantities of untreated effluents have been identified in this survey.

French clones have been widely propagated in wine countries around the world since the 70’s. Among this palette, clones of Cabernet-Sauvignon took a large place in the reputation of the French clonal material. Three emblematic clones of Cabernet-Sauvignon N — 191, 337 and 341— contributed to the success of wineries in France and abroad. These three clones tested positive for GRLaV-2. In France, we still consider that effects and symptoms of GLRaV-2 on vines are of poor impact on growth and quality on the wines. 191 and 337 have been recently cleaned-up by IFV, formerly ENTAV, using the micro shoot tip culture (MSTC) method. As agronomic and genetic profiles are required for the French official registration, in addition to sanitary testing by indexing, the “new candidate clones” were planted in an experimental vineyard, located in an INRA unit which was in charge of the vineyard management. Viticultural checking, wines and tastings by a panel have been carried out by Chambre d’Agriculture de la Gironde. This presentation provides the final results with detailed performance of five clones involved. Two clones have been registered in 2010 by the Vine Section of the Technical Permanent Committee for Selection (CTPS), 1124 (191 MSTC) and 1125, no micro shoot tip cultured, an “offspring” of the historical and original vine of 337. Five years of experimentation provided the following results: • 1124 : higher vigour, slightly higher producer in comparison with 191. Its fertility is higher, bunches are bigger, anthocyanins are also more present and its wines are structured and balanced. • 1125 : more fertile than 337, bunches are smaller, wines are aromatic and full. • 337 MSTC did not perform as well as the original 337 (LR2 +), and, above all, wines have been less appreciated than 337. A decision for its registration has not been made.

International audience

Recycling vine wood pruned in winter in the vineyard, after grinding and composting, might pose a risk of recontamination with fungi associated with grapevine decline. The survival of four ascomycete fungi (Botryosphaeria obtusa, Phaeomoniella chlamydospora, Phaeoacremonium aleophilum and Eutypa lata) in composted material was investigated in a 3-year study conducted in the Bordeaux area. Naturally and artificially infested material was examined before and after composting using classical isolation procedures. Results clearly showed that a composting process can eradicate the four target fungi efficiently.