What is the leaflessness of the vine?
The management of the vineyard during the growth period of the plant (also called green or leafless management of the vine ) groups a series of works that allows modifying its vegetative development and that, therefore, influences the yield of the crop, the quality of the fruit and its sanitary state.
Among them we find leaf removal , a technique that consists in the elimination of the basal leaves of the branches , that is, those leaves that are in the vicinity of the clusters (Figure 1).
When is leaf stripping done?
Traditionally, leaf removal is carried out during the ripening season of the bunch, normally in those plantations with excessive foliar density.
Why is the vine stripping done?
Among the objectives sought, this leaf removal seeks to be a preventive measure against different rottenness , since the elimination of these leaves increases the porosity of the canopy, which favors aeration and solar exposure of the cluster area, and generates a better thermal, hygrometric and light microclimate .
The leaf removal or removal of the basal leaves increases the crop yield, the quality of the fruit and its health.
As a consequence of this greater solar exposure, this defoliation also improves the coloration and aromatic quality of the berries , and leads to a more heterogeneous ripening throughout the bunch.
Likewise, by removing part of the plant’s foliage, this practice facilitates manual harvesting and increases the effectiveness of phytosanitary treatments (Tardáguila 2009).
The early leaf removal.
However, in recent years it has been proposed to bring forward leaf removal to the flowering season (early leaf removal) as an effective measure to regulate grape production and improve its quality.
What is the basis for early vine leaf removal?
This technique is based on generating a reduction in the amount of sugars available in the plant for the development of the inflorescence as a result of the elimination of said leaves, since at the time of flowering they carry out a very high photosynthetic activity that supposes the main source of sugars to ensure correct fruit set and development of the inflorescence (Vasconcelos et al., 2009).
What are the benefits of early leaf shedding?
In general, this practice generates bunches with a lower weight and, what is more interesting, a smaller number of berries, which gives rise to bunches of less compactness and, therefore, less predisposition to diseases and pests (eg. : Botrytis, powdery mildew, cluster moth), which globally improves its quality (Poni et al., 2006).
In a recent study on vine leaf removal, Acimovic et al. (2016) evaluated the effect of different degrees of severity of early leaf shedding (elimination of 0, 4, 6, 8 or 10 basal leaves) in the Pinot Noir variety, in order to establish a recommendation regarding the number of leaves eliminated. it means.
The authors observed that the removal of six or eight leaves was the most adequate to reduce the inflorescence set rate without negatively influencing the vineyard yield in the following years.
This lower fruit set rate significantly reduced the number of berries and the compactness of the bunch, generating an improvement in the overall quality of the fruit.
It should be noted that both leaf removal (classic and early) can be done manually or mechanically , through the use of pneumatic air jet leaf removers (Figure 2).
The use of these mechanical leaf removers allows a large number of plants to be removed per unit of time, presenting itself as an economically viable technique for our plantations.