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The storage of carbohydrates (sugars) in different parts of the grapevine (canes, trunk and roots) was studied from 1998 to 2002 on Chasselas cultivar by Agroscope Changins- Wädenswil ACW at the Pully experimental vineyard. The vine primarily stores its carbohydrates, mainly as starch, in roots and trunk. During the winter, starch is partially converted into soluble sugars (sucrose, glucose and fructose) in trunk and canes, to provide protection against dropping temperatures and risk of tissues frost. A significant mobilisation of starch was observed in roots and trunks from budbreak to flowering, resulting in their lower starch reserves. The starch level increased in roots and trunks from flowering stage until harvest and sometimes until leaf fall. The leaf-fruit ratio, expressed by the “light-exposed leaf area (SFE)/kg fruit”, largely influenced starch and total carbohydrate contents in the roots and trunks at the harvest. In our experimental conditions, starch and total carbohydrates contents in the roots were at peak levels when the leaf-fruit ratio reached 1.5 m2 of SFE/kg.

Keywords: carbohydrate reserves, leaf-fruit ratio, grapevines

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

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Grape clusters of different genotypes, including Vitis vinifera cvs Chasselas and Merlot, and two interspecific grape varieties, Solaris and 2091 (Gamaret x Bronner) were inoculated with Plasmopara viticola at three developmental stages (BBCH 53, 69 and 75). Samples were examined by scanning electron microscopy and synthesis of stilbenic phytoalexins was measured. At BBCH 53, zoospores germination was observed on all tested cultivars and three types of functional stomata were set up. At this stage, resistant cultivars produced a significant accumulation of toxic stilbenes, which stopped the further development of downy mildew. At BBCH 69 and 75, stomata are no more functional and none of P. viticola infection was successful. This result is confirmed by the absence of stilbenes induction at these stages on resistant grapevine cultivars. The structural changes in stomata anatomy during cluster development induce the onset of ontogenic resistance.

Keywords: downy mildew, cluster, grapevine, lenticels, ontogeny, resistance, stilbenes, stomata

E-Mail: katia.gindro@acw.admin.ch

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Roman chamomile (Chamaemelum nobile) is a perennial plant cultivated in the La Côte area (Vaud, Switzerland), for essential oil production. Since a few years, more and more fields show a mediocre vegetation re-start at Springtime, inducing plants’ progressive weakening and decline. In addition to the yield loss, essential oil quality decreases. A study was conducted in 2011 to identify the possible causes of this syndrome, focusing on three aspects: water stress, weeds influence and pest insects impact. Several causes seem to generate the phenomenon. Comparative tests in containers showed a relatively high sensitivity of roman chamomile to lack of water. Cultures are mostly not irrigated and certainly suffered from recurrent water shortfall during the past years. German chamomile (Matricaria recutita) is a concerning weed: very competitive and difficult to control, it becomes more and more present. Black medic (Medicago lupulina) forms scattered but very dense colonization zones, quickly excluding Roman chamomile. Among pests, the chrysomelid (Chrysolina marginata) severely contributes to plants’ decline by attacking the new emerged leaves at the end of the winter. The detection of these factors allows the setting of preventive and curative strategies to ensure economic viability of chamomile essential oil production.

Keywords: medicinal plants, chamomile, irrigation, weeds, Mordellidae, Chrysolina marginata

E-Mail: catherine.baroffio@acw.admin.ch

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In Quebec, the toxicity of six insecticides was tested in laboratory on Neoseiulus fallacis female, a predatory mite against Tetranychidæ pests in vineyards and orchards. Two insecticides (spinetoram and clothianidin) proved to be toxic for N. fallacis (more than 85 % of mortality) and should’nt be used in Integrated Pest management (IPM); the insecticide spirotetramat was moderately toxic (over 60 % of mortality) and stopped eggs laying and it should be avoided in IPM; three insecticides (novaluron, chlorantraniliprol and flubendiamid) were slightly or not toxic (under 20 % of mortality) and can be used in IPM.

Keywords: Integrated Pest Management (IPM), insecticides, predatory mite+mortality

E-Mail: dominique.fleury@eichangins.ch

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Pelargonium production occurs between February and May, an enabling period for temperature integration (IT). Trials were condcucted between 2009 and 2011 by Agroscope Changins- Wädenswil ACW to assess its energy saving potential as well as its impact on the plants. In 2009 the energy savings obtained in the IT greenhouse were very weak compared to the control (2.5 %). In 2010 and 2011 in return, the gain was respectively 32 % and 40 %, corresponding to 10 kWh/m2. Depending on the year and the varieties, the temperature had a significant effect on the main stem’s length, with a higher elongation in the IT greenhouse. Temperature integration had an effect neither on floribundity, nor on the plants’ fresh and dry weight.

Keywords: energy saving, stem’s length, fresh weight

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

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The Pink Lady® apple is problemless in cold storage for internal quality but it is susceptible to two storage diseases: common scald and internal browning. Different storage conditions were tested during four years in order to reduce their occurrence. Under ULO (ultra low oxygen) conditions, scald development could be avoided. The use of 1-MCP (Smart Fresh™) was in return only partially effective against this storage disease. In our tests, scald developed mainly in the stem cavity of the fruits despite of this treatment. Storage at higher temperatures from 3.5 to 4 °C reduced the appearance of internal browning. Smart Fresh™ also had a good effect against the disease. However, the results with the different storage conditions during the four years have shown that the influence of climatic conditions of a year and the influence of the orchard may be very high. Currently, no storage conditions can be recommended to prevent internal browning after six months of cold storage. In conclusion, according to our results it is recommended to store Pink Lady® apples under ULO conditions at a temperature from 3.5 to 4 °C. The control of the appearance of internal browning is highly recommended since April.

Keywords: storage, common scald, controlled atmosphere, internal browning, quality, ultra low oxygen (ULO)

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

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