Pre-flowering leaf removal alters grape microbial population and offers good potential for a more sustainable and cost-effective management of a Pinot Noir vineyard

Abstract

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, preflowering 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

Characterization of fungal communities of developmental stages in table grape grown in the northern region of South Africa

“…As expected, the Shannon-Weaver diversity index revealed that, samples at the inside centre of the vineyard were richer than samples at the peripheral end of the vineyard. This could be explained by variability in temperature, humidity and UV-light within a block or vineyard, as highlighted in previous studies (Sternad Lemut et al 2015;Sui et al 2015). On another note, environmental conditions, such as solar radiation interfere with the production, germination and survival of conidia, which affect the life cycle of the pathogen.…”

“…Sunlight exposure is generally high on vines at the peripheral end compared to the inside central vines due to canopy effect, this could result in a sterilizing effect on the bunch surfaces caused by UV radiation from sunlight, hence affecting the microbial composition and population. Previous researchers have also found that canopy microclimate conditions (air circulation, temperature and humidity) in grapevine (Sternad Lemut et al 2015) influence incidence of microbial infection in grapes. Furthermore, relative humidity in apples surfaces (Lahlali et al 2008) enhance the population of antagonistic yeasts.…”

“…This could be explained by variability in temperature, humidity and UV‐light within a block or vineyard, as highlighted in previous studies (Sternad Lemut et al . ; Sui et al . ).…”

“…Previous researchers have also found that canopy microclimate conditions (air circulation, temperature and humidity) in grapevine (Sternad Lemut et al . ) influence incidence of microbial infection in grapes. Furthermore, relative humidity in apples surfaces (Lahlali et al .…”

The Effect of Early and Late Defoliation on Phenolic Composition and Antioxidant Properties of Prokupac Variety Grape Berries (Vitis vinifera L.)

“…Early defoliation decreases berry weight and thus grape yield itself [10,13], while defoliation during or after veraison affects primary and secondary synthesis of metabolites [19,20]. On the other hand, some reports have shown that early leaf removal is capable of improving the grape and wine quality [21,22]. Leaf removal before flowering decreased the grape yield of the Sangiovese variety, but on the other hand, it increased concentrations of anthocyanins and other phenolic compounds, due to changed microclimatic conditions in the zone of grape clusters [16].…”