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Merello and Gamarello, both products of Merlot x Gamaret crossings, are two Vitis vinifera grape varieties recently created by Agroscope. Both varieties boast a high adaptive plasticity as well as a resistance to Botrytis cinerea inherited from Gamaret. Since the approval of the varieties in 2017, oenological trials have been conducted on Agroscope’s experimental cellar in Changins in order to discover how best to express their potential and unique qualities. This article studies the influence of length of maceration on the wines several months after bottling and again after 3 to 5 years of cellaring. Overall, the influence is greater for wines from the Gamarello variety, which develop greater aromatic intensity than those from the Merello grape. Vintage also has a significant effect on the impact of length of maceration. When determining the ideal length of maceration, the grapes and their phenolic ripeness at the time of harvest must be taken into consideration.

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

E-Mail: marie.blackford@agroscope.admin.ch

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The invasive brown marmorated stink bug (Halyomorpha halys) was accidentally introduced into Switzerland around 2004. This pentatomid is highly polyphagous and all its stages
are found on grapes. Here, we studied the impact of processed
H. halys on the aroma and taste of grape juices, musts and wines. We artificially contaminated Chardonnay and Merlot grapes with up to 10 nymphs and adults per kilogram grapes directly before their crushing. In the freshly pressed musts, the aroma
and taste of Chardonnay and Merlot juices contaminated with 3 to 10 H. halys individuals/kg grapes could be distinguished from uncontaminated controls and they were perceived as vegetal and woody. Yet after bottling, the different wines with 0 to
10 bugs/kg grapes could no longer be differentiated from each other and their sensory profiles were nearly identical. One year after bottling, invited winegrowers also did not dislike the H. halys contaminated wines compared to their uncontaminated controls. The molecules responsible for the off-flavours in contaminated musts therefore seemed to volatilise during fermentation. Our results consequently indicate that a contamination of the vintage with H. halys has the potential to alter the quality of grape juices and musts but that there is little risk for influencing the taste of processed wines.

Keywords: Vitis vinifera, Pentatomidae, Hemiptera, wine making, sensory analyses, organoleptic tests

E-Mail: patrik.kehrli@agroscope.admin.ch

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