Archives

In this study, Chasselas vines which were infected with Leafroll Virus 2 (GLRaV-2) alone or in combination with Leafroll Virus 4 (GLRaV-4) were compared with healthy vines. The observations, which were made from 2006 to 2018 on Agroscope’s experimental farm in Nyon, were related to agronomical and oenological aspects. The results show that the GLRaV-2 virus had virtually no effect on vegetative and production-related parameters. The combination of GLRaV-2 and GLRaV-4 led to a slight decline in vigour and production potential (bud fertility, average grape weight) as well as to a slight increase in sugar content and assimilable nitrogen content in the must. The different variants had no impact on the quality of the wines produced.

Keywords: grapevine, GLRaV-2, GLRaV-4, agronomical features, mineral nutrition, wine quality.

E-Mail: jean-laurent.spring@agroscope.admin.ch

Adress: Agroscope, 1009 Pully

Important agronomic and environmental issues, such as the use of herbicides, soil protection, the promotion of biodiversity or the quality of the harvest are impacted by the installation of ground covers in vineyards and orchards. Therefore, numerous developments and experimentations are currently carried out in the installation and management of green covers in these perennial crops. These trials require regular assessments of the vegetation and its evolution. A standardized protocol for vegetation monitiring, based on comparative trials and literature data, is proposed. The method relies on visual estimates of specific coverage rates, which distinguish about ten cover classes. This protocol represents a good compromise between precision and speed of implementation. It optimize possibilities for comparisons and exchanges of information.

Keywords: ground cover, vineyards, orchards, vegetation monitoring, flora survey

E-Mail: nicolas.delabays@hesge.ch

Adress: Hepia, 1254 Jussy

Why shall we defoliate the vines? Which period? Which intensity? And at what risk? These recurrent questions are asked every year at the beginning of the vegetative season of the vine, while the canopy is developing, sometimes even with vigor. Pre-flowering leaf removal is an interesting prophylactic technique to control yield, increase resistance to fungal diseases and modify the organoleptic profile of wines, but it can also present risks. This article provides an overview of the current knowledge on vine leaf removal and reports on five trials conducted in the experimental vineyards of Agroscope in Switzerland. Pinot noir, merlot, gamay, chasselas and doral grape varieties were defoliated at different phenological stages and different intensities, in order to provide answers to the winegrowers.

Keywords: leaf removal, yield regulation, wine composition

E-Mail: thibaut.verdenal@agroscope.admin.ch

Adress: Agroscope, 1009 Pully