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Biological control in Gerbera cut flower crops is interesting because only flowers are harvested. Thus minor injuries on leaves can be tolerated. Three years of trial and follow-up on this culture showed that the populations of thrips and mites are overall well controlled. However whitefly control remains the principal difficulty. The parasitoids Encarsia formosa and Eretmocerus eremicus as well as the predatory bug Macrolophus caliginosus gave disappointing results. On the contrary, the predatory mite Typhlodromips swirskii, not yet registered in Switzerland, showed interesting results in whitefly controlling.

Keywords: biological control, gerbera, whitefly, Typhlodromips swirskii

E-Mail: celine.gilli@acw.admin.ch

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To answer the requirements of producers and industry, a research programme aiming at finding natural sources of geraniol was initiated at the beginning of the years 2000. The comparison of three species within the northern American genus Monarda allowed to highlight the qualities of the clone «Morden #3», a geraniol chemotype (> 90%). This triploid hybrid developed by the research station Morden in Manitoba (Canada) showed its suitability to the pedo-climatic conditions in a Swiss mountain area: very good winterhardiness, good dry material productivity (4-5 t/ha) and a high essential oil content (3.5-6%). Recent works allowed to partly characterise and quantify the hydro-alcoholic extract of the leaves. The leaves contain byproducts of cafeic acid, among others rosmarinic acid (1.7% in the leaves) and flavonoids.

Keywords: rosmarinic acid, cutting frequency, flavonoids, geraniol, Monarda didyma

E-Mail: claude-alain.carron@acw.admin.ch

Adress: Agora

Mating disruption to control codling moth C. pomonella was tested from 1982 to 2006 in an apple orchard of 6 ha in Allaman, using different kinds of dispensers. During these 25 years, almost all insecticidal treatments after flowering could be avoided, whereas chemically protected Swiss orchards were treated each year 2-3 times against codling moth, sometimes more often in the presence of resistant strains. The obtained results varied little relative to experimental dispensers tested and load of pheromone applied per ha. The range of Isomate dispensers currently registered leads to very good results, so far as application recommendations of the mating disruption technique are carefully respected. When conditions are extremely favourable for codling moth, as in 2003, mating disruption as well as classical control cannot prevent an increase of the populations. This article shortly relates the means used to fight against summer fruit tortrix Adoxophyes orana, winter moths and noctuids, small fruit tortrix Grapholita lobarzewskii and aphids.

Keywords: Codling moth, Cydia pomonella, mating disruption, dispensers, damage, population dynamics

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

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The rootstocks M20, M27, P22, P16, Supporter 1, Supporter 2 and two clones of M9, Burgmer 984 and FL56, were between 1994 and 2002 compared to the control EMLA. The evaluation was based on the clone B type GD 85 of the variety Golden Delicious. M20, M27 and P22 reduced vigour by 65% and Supporter 1 and Supporter 2 by 30-40%. Burgmer 984 und FL 56 with 6 and 20% reduction, respectively, did not differ significantly from the control. P16 guaranteed in relation to vigour the best productivity and due to increased fruit calibre the highest proportion of commercial quality. In contrast, this rootstock was placed last concerning sugar content and firmness. Best values were obtained by M27, P22 und M20. The three clones of M9 reached below average sugar values and a satisfactory firmness. Except with P16, a weak vigour favoured sugar content, but did not influence calibre and firmness, which are mostly determined by average fruit weight. This explains M20 and P16 bad results.

Keywords: rootstock, M9, apple, production, vegetative growth, fruit quality

E-Mail: alberto.sassella@acw.admin.ch

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A study on plant density was carried out in 1994, using Gamay vines on the experimental estate of 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, the sugar concentration in must wasn’t affected by increasing distances between rows and plants. The ratio of exposed leaf surface per kg of grapes (SFE/kg) was a valuable tool in explaining this absence of effect. A ratio of SFE/kg equal or higher than 1 m2 was obtained for the whole variants. No significant effects of plant density were noted on the pruned wood weights per plant, the weight of berries, bud fertility or on the components of must and wine acidity. Raising distances that separate the rows tended to reduce potassium level in leaves. From the wine-tasting point of view, the increasing distance between rows didn’t affect the wine quality, considering that a sufficient ratio SFE/kg was maintained on the whole variants.

Keywords: plant density, hedgerow height, wine quality

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

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The Agroscope Changins-Wädenswil Research Station ACW set up an experimental trial to compare the physiological behaviour of old and young vines. Six different varieties (Chasselas, Pinot blanc, Arvine, Gamay, Syrah and red Humagne) were included in the study which was made on the experimental estate at Leytron (Wallis, Switzerland) between 2002 and 2006. Young vine plants were more subject to conditions of water stress than old vines because of their superficial root systems. In the present study, moderate water stress in young vines was observed in 2005 and 2006 whereas old vines showed low stress for the same period. Plant growth in older vines was greater than that of the younger grapevine plants, irrespective of variety. Not only was the weight of clippings and pruned wood found to be higher in old vines, but also values of the chlorophyll index and nitrogen content in leaves.

Keywords: grapevine age, leaf water potential, photosynthesis, vigor, microclimate

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

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A technique for rapid in vitro propagating of wormwood is described in this study. Young leafy shoots of wormwood were cultivated on a basal Murashige and Skoog (1962) salts medium supplemented with 0.5 mg/l Benzyladenin (BA) and 0.01 mg/l Indolebutyric acid (IBA) to induce the development of new shoot buds. Adventitious root formation was achieved by transferring young leafy shoots on hormone-free medium. In vitro rooted plants were successfully (> 95%) acclimatised and transferred to field conditions.

Keywords: wormwood, Artemisia absinthium, tissue culture, BA

E-Mail: cong-linh.le@acw.admin.ch

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During the years 2003 to 2005, the ripening of Gamaret was followed on fifteen plots using two methods: sensory analysis of berries and analysis of anthocyanins to monitor the evolution of phenolic compounds. In four cases, berries were harvested at three to four successive dates. Wines were analysed using flash profiling. Sensory analysis of berries provided reliable information on organoleptic qualities of the berries. Descriptors efficiency was influenced by the grape variety and the vintage. A selection of efficient sensory descriptors for Gamaret could be defined. The evolution of anthocyanins in the berries during ripening is independent of other compounds such as sugar and acidity. A better interpretation of anthocyanins measures is obtained using a tendency curve (polynomial of degree two). The wines coming from the last harvest date have the higher colour concentration and are preferred in wine tasting. They are considered more intense, complex, round, vinous and with a better tannic constitution. The third harvest date occurred in average twelve days after anthocyanins have reached a maximum.

Keywords: ripening, maturation, phenolic compounds, anthocyanin

E-Mail: simone.demontmollin@usoe.ch

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