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New constraints and requirements have recently appeared in the field of viticulture. Firstly, the range of herbicides available to the practitioners of viticulture has been markedly reduced; this is as much the consequence of numerous withdrawn registrations, as that of restrictions enforced now in several different production systems and labels. Secondly, there is a consensual awareness nowadays that soils and their fertility need better protection, what generates new constraints in areas such as weeding techniques, with a special emphasis on mechanical soil management.Thirdly, the increased support for biodiversity in the agricultural landscape has substantially complicated the management of the spontaneous flora within the vineyards. This article itemizes and describes these new constraints, while presenting their consequences for the practice of viticulture. The article also presents the available solutions and discusses the need for further innovations.

Keywords: vineyards, weed management, flora, biodiversity.

E-Mail: nicolas.delabays@lausanne.ch

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The oomycete Plasmopara viticola, causal agent of grapevine downy mildew disease, constitutes the most destructive pathogen in regions with rainy springs/summers. Genetic analysis on P. viticola populations collected in Europe (eight of them in Switzerland) allowed reviewing the classical assumption of its epidemiology. In fact oosporic infections do not only start the disease at springtime, as speculated in the past, but continue to occur throughout the grape growing season. Clonal infections were shown to play a relevant role mainly at vine scale and seldom at vineyard scale, in sharp contrast to previous beliefs about the major importance of asexual inoculum. The importance of those findings consists in a change of the traditional concept of the P. viticola epidemiology and its effect on control strategies.

Keywords: downy mildew, Vitis vinifera, population genetics, epidemiology, SSR.

E-Mail: mauro.jermini@agroscope.admin.ch

Adress: Agroscope, 6593 Cadenazzo

The use of hot water to decontaminate nursery stock from fungal pathogens has been proposed by different authors, but the efficacy of such treatments is still controversial. For instance, some authors reported a complete removal of fungal pathogens after hot water treatment of dormant canes, while others reported no differences in vascular discoloration and pathogen isolation between treated and non-treated dormant cuttings. This study reports the occurrence of fungal species isolated from nursery-plants after hot water treatment (45 minutes at 50 °C). Treated and non-treated plants of five different cultivars were analysed (Chasselas, Gamay, Gamaret, Arvine and Humagne) and the fungal communities were compared between cultivars and among treated and control plants. Great differences among fungal communities living in the different cultivars were observed. Hot water treatment affected the isolation frequency of several species of the fungal community within each cultivar. For instance, several of these species were isolated with a lower frequency compared to the control plants, while other species were isolated only after the treatment. The reduced presence of pathogenic fungi confirms the potentialities of hot water treatment in plant sanitization, but the presence of other plant pathogens raises doubts about the role and interactions of fungal species inside Vitis plants.

Keywords: Vitis vinifera, Petri disease, fungal community, hot water treatment.

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The effect of wine makings on lees was tested in 2005, 2006 and 2007 with Chasselas wines to limit the appearance of flavour defects related to a nitrogen deficiency of the musts. The results show that these wine making practices do not allow preventing this particular defect which characterizes these coarse, bitter and astringent wines.

Keywords: nitrogen composition, nitrogen competition, wine making on lees, stress, wine quality, yeast.

E-Mail: fabrice.lorenzini@acw.admin.ch

Adress: Agroscope, 1260 Changins/Nyon

In Switzerland, thrips (mainly T. tabaci) infestations often lead to substantial damage on leek crops in spite of a large variety of approved insecticides. Field experiments were realised in 2008 by ACW atWädenswil in order to evaluate the efficacy of chemical control methods against thrips. A first assay conducted over a short cultural period (eleven weeks) revealed a good efficacy of the insecticides Perfekthion, Audienz and Vertimec after three consecutive applications. However, in a second assay realised to protect leek over the whole growing period, neither alternate applications of carbamates and organophosphates, nor multiple treatments with pyrethroids prevented substantial damage symptoms at harvest. The efficacy of insecticides can be improved by optimising the spraying techniques, as well as the timing and frequency of treatments during the season. However, alternative control methods should be developed for a better control of thrips damage on leek crops.

Keywords: Thrips tabaci, leek, carbamates, organophosphates, pyrethroids, spraying technique, non-chemical control.

E-Mail: juergen.krauss@agroscope.admin.ch

Adress: Agroscope, 8820 Wädenswil

Apricot production in Switzerland is mainly devoted to fresh market and distillery. Apricot kernels from the distillery are considered as waste. Until now, no concerted use of the kernels is organised in order to valorise them. The aim of this study was to analyse the chemical composition of oils from kernels of different apricot cultivars in comparison with two commercial oils. The analyses revealed a high content in linoleic acid (omega-6), oleic acid (omega-9) and in vitamin E. The level of amygdalin (toxic compound responsible for the bitterness) was moderate. Protein content in the oil cake was quite high (20-30%). The cultivar Luizet differed little from the other cultivars studied and from the commercial oils. The valorisation potential of oil issued from Luizet kernels, particularly in cosmetics or human nutrition, is discussed.

Keywords: apricot kernel, by-product, oil, amygdalin, linoleic acid, oleic acid, vitamin E.

E-Mail: danilo.christen@acw.admin.ch

Adress: Agroscope, 1964 Conthey

Studies on fungi associated with Vitis vinifera, essentially focused on esca symptomatic plants, have shown that many and systematically diverse fungi are present in diseased wood. Among these fungi, several have also been isolated from healthy grapevine plants. The shift from a saprotrophic/endophytic to a pathogenic behaviour suggests that the fungal community associated with grapes is unbalanced through time. To investigate the fungal community associated with V. vinifera, the esca-sensitive cultivar Chasselas was chosen to isolate fungi growing from both surface-sterilised apoplectic and young asymptomatic wood. The isolates were characterized based on morphology and ITS sequences. Our molecular classification is based on four loci. Fungal communities retrieved from symptomatic and asymptomatic grapes are dominated by Sordariomycetes, mainly Hypocreales and Xylariales, but they differ among each other partially in their respective species composition. Using both our own sequences and existing data produced by the project ‘AFTOL’, the phylogenetic placement of some species of incertae sedis was inferred within the ascomycetes and the potential of the genes sequenced was explored to design molecular tools for different systematic ranks to study the evolution of the fungal community in grapevine wood.

Keywords: Vitis vinifera, multilocus phylogeny, RNA polymerase II second largest subunit (RPB2), ribosomal mitochondrial small subunit (mitSSU), ribosomal nuclear large subunit (nucLSU), transcription elongation factor 1-alpha (tef-1).

E-Mail: valerie.hofstetter@acw.admin.ch

Adress: Agroscope, 1260 Changins/Nyon

Depuis 1973, la Fondation Lotte et Willy Günthart-Maag de Regensberg (ZH) décerne chaque année le prix Rudolf Maag à une personnalité suisse ou étrangère qui s’est particulièrement distinguée dans le domaine de la production ou de la protection végétale. Cette année, ce prix a été décerné, le 10 juin dernier, à Madame Catherine Lambelet, conservatrice aux Conservatoire et jardin botaniques de la ville de Genève (CJBG). Depuis de nombreuses années, Mme Lambelet travaille en étroite collaboration avec la Station de recherche Agroscope Changins-Wädenswil ACW. Elle s’est toujours souciée d’allier le respect de la nature aux contingences agricoles.

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Adress: Office fédéral de l'agriculture