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Autonomous mowing and complete floor cover for weed control

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  AIM: Enhancing vineyards sustainability and reducing herbicide usage is a crucial theme, thus alternative weed management methods are starting to be studied. The aim of this trial was to evaluate if the combination of cover crop species and autonomous mowers management could improve vineyard sustainability. BACKGROUND: Cover crops have been shown to provide for several environmental services such as performing an efficient weed control and promoting biodiversity, thus improving the sustainability of the overall management system. However, the use of cover crops is usually confined to the interrow area in order to avoid competition with vines. Under-trellis weed management in vineyards is an important challenge, conventionally fulfilled by cultivation or repeated herbicides applications. Autonomous mowers are small autonomous machines that have shown a great efficiency when employed in agricultural contexts. Due to their reduced size, they can easily prevent the excessive vertic

Kaolin application modulates grapevine defense response

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AIM & METHODS: At a local scale, kaolin particle-film technology is considered a short-term adaptation strategy to mitigate the adverse effects of global warming on viticulture. This study aimed to evaluate kaolin application effects on photochemistry and related defense responses of  Touriga Franca  (TF) and  Touriga Nacional  (TN) grapevines planted at two Portuguese winegrowing regions (Douro and Alentejo) over two summer seasons (2017 and 2018). For this purpose, chlorophyll  a  fluorescence transient analysis, leaf temperature, foliar metabolites, and the expression of genes related to heat stress ( VvHSP70 ) and stress tolerance ( VvWRKY18 ) were analysed. RESULTS: Kaolin application had an inhibitory effect on  VvHSP70  expression, reinforcing its protective role against heat stress. However,  VvWRKY18  gene expression and foliar metabolites accumulation revealed lower gene expression in TN-treated leaves and higher in TF at Alentejo, while lipid peroxidation levels de

The dual roles of Starmerella bacillaris wine yeast

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Role #1: Starmerella bacillaris  is a non- Saccharomyces  yeast recently proposed for grape fermentation in association with  Saccharomyces cerevisiae . Due to its high glycerol and moderate volatile acidity production this yeast can contribute to improving wine quality. Previous research has also demonstrated that S. bacillaris has a lower sugar to alcohol conversion compared to S. cerevisiae , and in addition, it is also fructophillic. Role #2 : Some strains have been demonstrated to exhibit antifungal activity against grey mould on grape, which is caused by  Botrytis cinerea . The simultaneous presence of these traits in  S. bacillaris  is of great interest. Indeed, this yeast can be potentially used as a biocontrol agent in vineyards. Research on the ability of  S. bacillaris  to survive or, even to grow on the surface of grapes is a starting point in the evaluation of its potential use in vineyards.   EXPERIMENTAL LAYOUT Each grape bunch was dipped in a Starmerella baci

How to increase pyrazines in Shiraz (or not)

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The aim of the study was to establish the influence of MOG (matter other than grapes) included in fermentation on the chemical and sensory profiles of Shiraz wines. PROJECT LAYOUT: Five different treatments: Control – berries only Berries and leaves (1% w/v) Berries and rachis (2.6% w/v) Berries and peduncles (1.5% w/v) No fermentation on the skins (rosé) Shiraz grapes from Adelaide Hills were harvested at 23.1°Brix and divided in 13 batches of 50 kg each. Two batches were used for controls and two for rosé fermentations. Remaining nine batches were used for triplicate MOG treatments. Wines were fermented with EC1118 and after completion sulphured, filtered, bottled under screwcap closures, and stored at 15°C. Chemical and sensory analyses were performed 14 months after completion of fermentation. MAIN RESULTS: The addition of leaves increased red fruit and confectionary aromas in the wines compared to the control. The addition of peduncles enhanced green, overall f

Influence of curettage on Esca-diseased Sauvignon blanc vines

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Aim of the study:    A study on Sauvignon blanc (SB) cultivar in France showed that curettage had an effect on the resilience of grapevine trunk diseased (GTD) grapevines. No experiments, however, have been conducted on its effects on wine quality, particularly on white SB cultivar wines. In this study, the effect of Esca on the must and wine quality of SB was investigated. Methods and results: Grapevines from Sauvignon blanc cultivar that had expressed Esca-foliar symptoms were used for the study, with some of them having been curetted in 2014. Subsequently, bunches from Control (asymptomatic), Curetted and Esca-symptomatic vines were harvested in 2017 and 2018 in order to produce white wine. Technical and chemical results on both must and wine showed that wines from curetted plants were similar to those from asymptomatic vines. There were differences, however, for Esca-diseased vines, where the alcoholic fermentation of musts was faster than for the other modalities. Olfactometry

Suppressive soils specific to ring nematodes

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New Winetech funded viticulture project 2021:   This study will aim to detect, identify and characterize soils that maintain specific natural suppressiveness to ring nematodes, leading to the identification of improved agricultural practices to conserve and enhance these soils.   Ring nematodes ( Criconemoides xenoplax ) are one of the most common and abundant nematode species in vineyards in the Western Cape. A 90% occurrence of the nematode has been recorded in vineyards in the Western Cape, with C. xenoplax being described as the key pest responsible for the damage observed on grapevines in South Africa. However, damage by ring nematodes is especially evident when vineyards are exposed to other stresses, such as poor soil conditions and water stress. Nematicides are not very effective in reducing the numbers of ring nematodes, because the nematodes occur very deep where nematicides do not reach, endorsing the need for alternative measures of control.   Evidence suggests th

Achieving industry sustainability through an effective premiumisation strategy for South African wines in global markets

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New Winetech funded marketing project 2021:    Despite a recent significant quality leap, the comparatively low status (e.g., “cheap and cheerful”) and value of South African wine on international markets remains a considerable source of concern for industry leaders. However, it is not entirely certain what factors account for this situation, why they are important, how they interact and therefore what effective differentiating factors can the SA category employ to improve value and status across the board in global value chains. Similarly, what can we learn from successful premiumisation strategies both within the SA and global context that will better inform future industry strategy and sustainability? Improving quality is only one aspect of the reputational challenges that wine categories face in order to influence their market status and the premium they can charge. Strategies such as category re-interpretation, signalling, allusion, niche-width reduction and so forth, may be goo