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A study on plant density was carried out in 1994, using Chasselas vines on the experimental estate of the Agroscope Changins-Wädenswil Research Station ACW in Leytron (Wallis, Switzerland). Variations in plant density were obtained by adjusting distances between rows and plants and heights of hedges. At comparative yields per unit surface area and same hedgerow heights, the sugar concentration in musts tended to decrease with increasing distances between rows. The ratio of exposed leaf surface per kg of grapes (SFE/kg) was a valuable tool in explaining sugar content in musts. Maximum levels of sugar were reached when the SFE/kg was above 1.0 to 1.2 m2. No significant effects of plant density were noted on the weight of berries, bud fertility or on the components of must and wine acidity. Raising distances that separate the rows caused a slight increase of shoot weight but a sharp drop in pruned wood weights per unit of soil surface. It also reduced potassium levels in leaves and the content of glycerol and superior alcohols in wines. From the wine-tasting point of view, at satisfactory SFE/kg ratios, widening interrow spacing tended to improve wine quality slightly.

Keywords: plant density, hedgerow height, wine quality

E-Mail: francois.murisier@acw.admin.ch

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To test the behaviour of four Pinot blanc clones, a trial was set up on the experimental vineyard of Agroscope Changins- Wädenswil Research Station ACW in Nyon (VD). The two clones of the French Catalogue (54 and 55) and one clone of the Italian Catalogue (SMA 102) were tested, as well as a candidate clone selected by ACW (RAC 28). The study showed that clone SMA 102 has a lower production potential than the other clones, but without positive effects on the organoleptic quality. Under our experimental conditions, which included yield regulation, no important difference could be highlighted between the wines, whether from the analytical or the organoleptic point of view. On the basis of the results obtained, the candidate clone of ACW will be multiplied and diffused within the framework of the Swiss certification system under the name RAC 28.

Keywords: grapevine, Pinot blanc, clones

E-Mail: dominique.maigre@bluewin.ch

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The study of the physiological behaviour of the grapevine (cv. Chasselas), and of plant hydraulics in particular, was conducted on various «terroirs» in the Canton of Vaud (Switzerland) between 2001 and 2003 by Agroscope Changins-Wädenswil Research Station ACW, in collaboration with the firm I. Letessier (SIGALES) in Grenoble and the Federal Polytechnic School of Lausanne (EPFL). An evaluation of the vine plant hydraulics was made by means of physiological indicators (leaf water potentials, carbon isotope discrimination and a model of transpirable soil water), in relation to estimations of the soil water reservoir and climatic factors. A close relationship came to light between the plant hydraulics, estimated by the predawn leaf water potential, and the reserves of useful soil water (RU), from a network of about 30 study sites over a period of observation covering three climatically different years (2001 very wet year, 2002 intermediate year, and 2003 dry year). Observations from the present study indicate that the carbon isotope discrimination technique (_13C) in grape sugars was closely correlated to the plant hydraulics noted in the vine during the ripening stage (phase of sugar accumulation in berries). The use of a transpirable soil water model (Riou and Payan, 2001; Lebon et al., 2003) allowed to determine levels of water stress from the different sites according to the three principal components:period, duration and intensity. The total of transpirable soil water (TTSW) was estimated by combining the model with values of pre-dawn leaf water potential. The estimations of TTSW and RU observed at the different study sites were in good agreement.

Keywords: «terroir», plant hydraulics, leaf and stem water potential, carbon isotope

E-Mail: vivian.zufferey@acw.admin.ch

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The larvicidal and ovicidal activity on grapevine moth L. botrana and grape berry moth E. ambiguella of some insecticides applied by dipping of bunches in different concentrations were tested. The larvicidal efficacy of most products was definitely higher on L. botrana than on E. ambiguella. LC50 of emamectin, spinosad, methoxyfenozide and indoxacarb was located between 0.003 and 0.05 ppm for L. botrana and between 0.03 and 0.3 ppm for E. ambiguella. Ovicidal effectiveness of fenoxycarb, a typically ovicidal product, and Lufox, a mixture of fenoxycarb and lufenuron, was stronger on E. ambiguella than on L. botrana. The other tested products did not show any ovicidal potential worthy of interest, except for methoxyfenozide and flufenoxuron, which were relatively effective on L. botrana.

Keywords: grapevine moth, grape berry moth, insecticides, ovicidal activity, larvicidal activity, Lobesia botrana, Eupoecilia ambiguella

E-Mail: pierre-joseph.charmillot@acw.admin.ch

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In order to satisfy enologists requirements, cross-flow (or tangential) filters are becoming more and more efficient and respectful to wine. Today, the evaluation of the new marketable apparatuses is necessary. In this paper, the results of a study comparing four cross-flow filters and focusing on filter’s performance and on the quality of final wines are given. They show that the actual filtration processes and the piloting system carry the same level of importance as the type of filter membrane (ceramic or polysulfone). A new generation of membranes made from polysulfone seems to be slightly more efficient than the ceramic membranes. From a microbiological standpoint, an average membrane pore diameter of 0.2 μm is able to retain the majority but not the totality of micro-organisms.

Keywords: cross-flow, tangential, filter, wine, oenology

E-Mail: julien.ducruet@eichangins.ch

Adress: Agora

Research on stone-fruit tree decline has been carried out since 2002 at Agroscope ACW experimental Stone Fruit Center at Breitenhof as well as in on-farm trials in different regions. T. basicola and Phytophthora spp. could be identified as the main agents responsible for stone-fruit tree decline, cultivation methods were defined to avoid further problems and trials were set up to test their efficiency. On the other hand it has been observed that a careful choice of the planting site and of tolerant rootstocks, as well as adapted cultivation of the trees permitted maintenance of healthy stone-fruit orchards even under conditions of high pressure of T. basicola. It is recommended to use only certified plant material for new plantations in order to avoid spreading of new or recently introduced quarantine diseases.

Keywords: stone-fruit, decline, Thielaviopsis basicola, Phytophthora spp

E-Mail: simon.egger@acw.admin.ch

Adress: INRAE, UMR LAE, 68000 Colmar

Common sage (Salvia officinalis L.) is one of the aromatic plants most cultivated in Switzerland. In order to guarantee an optimal sage harvest, the harvesting frequency as well as the height and date of the last cut before winter were analysed. These trials were conducted in Bützberg (Bern), Arbaz and Venthône (Wallis) from 2002 to 2006. With three cuts per year, the yield in dry material and in essential oil, as well as the leaves rate and the resistance to winter frost were generally higher than with two cuts. A last harvest early before winter, at the beginning of September, strengthened the resistance to winter frost only for the process with three harvests per year. With a cut at 15 cm for the last harvest, there were less damages caused by winter frost than with a low cut at 5 cm. But that higher cut favoured the formation of floral stems. Shortening the stubbles to about 5 to 10 cm after winter considerably reduced the formation of floral stems, not wanted for the sage. In conclusion, the productivity, winterhardiness and quality of the sage in a mountain area are favoured by three harvests per year with a last cut at the latest towards the beginning of September at a height of 15 cm, followed by a stubbles shortening to about 5 to 10 cm in the following spring.

Keywords: carbohydrates, quality, sage, winterhardiness, yield

E-Mail: christoph.carlen@agroscope.admin.ch

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