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Sunday, June 14, 2020

Leaf Pulling in Barbera

I came across this timely article called "Manual and mechanical leaf removal in the bunch zone (Vitis vinifera L., cv Barbera): effects on berry composition, health, yield and wine quality, in a warm temperate area". The results in this paper came from studies conducted in the northwest region of Italy between the years 2001-2003.
I read it with interest since this year we will hopefully have our first harvest of Barbera.
It turns out that Barbera is sensitive to fungal diseases, Botrytis cinerea grey mold in particular. Fruit-zone leaf removal is one of the most common summer practices aimed at an improvement of cluster microclimates, favoring grape ripening, reducing fungal diseases, and having an impact on the sensory properties of wines.
The ripening of Barbera is favored, especially in the latter stages, by a warm and dry climate, since as this variety has a highly acidic must and shows high vulnerability to Botrytis cinerea.
The authors found that the results of leaf pulling depended on the phenological stage of the grapes, the intensity of intervention, as well as on the climatic conditions of the season.
Climatic parameters that have an impact on berry composition, bunch health, vegetative growth and physiology include:
  • temperature
  • atmospheric humidity
  • solar radiation
  • water availability (rain or irrigation)
Leaf removal can improve cluster exposure and ventilation and the efficiency of pesticides, resulting not only in a considerable reduction in fungal diseases but also in better grape ripening and sensory properties of wines. Leaf removal however, had no impact on sour rot, a severe disease against which no effective protection product is currently available and it increased grape sensitivity to sunburn due to greater sunlight exposure.
References:
1. Silvia Guidoni, Gianluca Oggero, Bergio Cravero, Marco Rabino, Maria Carla Cravero, Paolo Balsari, Manual and mechanical leaf removal in the bunch zone (Vitis vinifera L., cv Barbera): effects on berry composition, health, yield and wine quality, in a warm temperate area, J. Int. Sci. Vigne Vin, 2008, 42, n°1, 49-58.

2 comments:

  1. We leaf pluck, manually, Pinot Noir on Mornington Peninsula, Australia. But we only pluck eastern side. In past where we have plucked both sides we found harsh afternoon Sun damaged bunches.

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  2. Hello! Thank you for your comment. We also manually leaf pluck around the fruit zone in our other varieties. We have found that leaf plucking on east and west sides of the canopy in our Auxerrois leads to sunburn. It appears that how you leaf pluck varies with the variety. Thank you very much for your comment and for reading my blog!

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