Background and Aims
Early defoliation has been proposed as a tool to reduce bunch susceptibility to fungal infections through a reduction in bunch compactness. This research aims to determine the ...desired level of defoliation producing looser bunches and to investigate the impact of the application of early defoliation on Pinot Noir vines under cool climate conditions.
Methods and Results
We applied leaf removal treatments at full flowering or EL‐20 phenological stage on Pinot Noir in 2 consecutive years using five levels of defoliation: no leaves removed, and leaves removed from four, six, eight and ten basal nodes. The effects on fruitset, bunch morphology, fruit chemistry, yield and rot severity were recorded. We identified the defoliation of eight basal nodes as the threshold resulting in significantly lower fruitset. The removal of eight or ten leaves reduced bunch compactness but did not alter the proportion of rot. Finally, fruit composition at harvest of the treated vines was found to be improved compared with that of the control vines.
Conclusions
The defoliation of six to eight basal nodes at full flowering can regulate fruitset and bunch compactness in Pinot Noir under cool climate conditions. Application over 2 years showed no adverse effects on bud fruitfulness or vine performance the following year.
Significance of the Study
Early leaf removal can be an efficient tool to alter bunch architecture, yield and fruit composition without impacting vine health.
Background and Aims
The grapevine canopy microclimate, particularly temperature and relative humidity, is of crucial importance for predisposing grapes to lower or greater incidence of microbial ...infections. Because of global warming, the widely adopted leaf removal at veraison causes an increase in the temperature of the grape berry surface, leading to sunburn and deterioration of berry composition. Seeking a good alternative, a novel, pre‐flowering leaf removal was studied and compared with post‐flowering approaches using a multidisciplinary approach.
Methods and Results
The effect of timing of leaf removal on the microbial ecology was studied in a Pinot Noir vineyard during two extremely different vintages. The effectiveness of leaf removal in suppressing Botrytis cinerea was compared with that of fungicide application. Bunch compactness and potential for cost and energy savings were calculated. The results showed that earlier leaf removal offers greater potential for successful control of microbial infections. Pre‐flowering defoliation also led to lower bunch compactness (16–18%) accompanied by a substantial yield reduction (30% in 2010 and 24% in 2011).
Conclusions
In addition to improved microbial control, the lower yield from pre‐flowering defoliation can eliminate the need for bunch thinning and consequently reduces total energy consumption; thus, the technique can be considered to have good potential for more sustainable and cost‐effective management of the vineyard, saving 27% on costs and as much as 46% on energy.
Significance of the Study
The sustainability of a novel pre‐flowering defoliation in Pinot Noir was evaluated by studying the microbial ecology of the vineyard and by calculating the potential savings from reduction in spraying and energy.
Wine colour depends directly on the quantitative and qualitative profiles of anthocyanins, flavonols and hydroxycinnamic acids, as well as on their involvement in polymerization and co-pigmentation ...reactions. Pinot Noir is a grape variety with a low natural colour potential, often combined with problems of low colour stability for its wines during aging. The influence of leaf removal timing on grape colour related polyphenols was observed during maturation and at harvest time for the 2009 vintage “real scenario” conditions in two different vineyards in the Vipava Valley (Slovenia), known for its warm but windy climate. With different timing of leaf removal, a different microclimate can be achieved, with different light exposure for the specific plant tissue and different temperatures on berry surfaces. Phenolic compounds were characterised and quantified using HPLC/Vis. Three classes of polyphenols were affected by leaf removal timing, but with differing intensities and with some differences between locations. Hydroxycinnamic acids were affected only slightly, mostly at the beginning of the maturation period. Anthocyanins were significantly affected, while flavonols were the most affected by treatments in both vineyards and their concentration was clearly related to modification of the light within the canopy.
The knowledge of spatial variability is particularly important and several studies were carried out around the world, since it has been speculated that the overall grape quality is negatively ...affected by the vineyard heterogeneity. Based on this, a project was carried out in “LA VIARTE” (one important winery in the Friuli Colli Orientali D.O.C. area) with the aim to examine the spatial variability of the whole viticultural surface in order to make thereafter decisions about possible applications of variable-rate technologies or selected harvest. During 2009 and 2010 several soil parameters (texture, moisture, organic matter, etc.), NDVI, stem water potential, yield and grape quality parameters were collected in more than 100 plots well distributed in the different vineyards in several timings along the season. Data were coupled with GPS position and processed into maps that were overlaid in order to distinguish the overall variability of the vineyards. Correlations among yield, quality parameters and vigour were then evaluated for each cultivar, and based on vigour, selected areas were divided within the vineyards to ascertain the grape performance. In 2010 wines were made from ‘Friulano’, ‘Sauvignon’, ‘Schioppettino’ and ‘Pignolo’ vineyards keeping separated the opposite vigour areas, and they were tasted by an expert panel. The results of the sensory coupled with the chemical analysis of wines highlighted the possibility to separate grapes in order to obtain basic and premium wines within the same vineyard. The decision between keeping or reducing the intra-vineyard variability throughout the application of VRT, will be a decision of LA VIARTE owners, based on the requests of the future wine market.
