Manual of techniques for sustainable mountain viticulture Josep Lluís Pérez Verdú

Manual of techniques for sustainable mountain viticultur

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•

Grass must be regularly cut (clearing) to work the land and improve the health conditions of the

crop. Cut grass is left on the terrace and a biotype is created that turns organic matter into humus,

thus increasing soil fertility and its resistance to degradation (erosion, compacting).

•

Grass avoids direct impact of rainwater on the soil, which decreases the formation of crusts that

favour surface run-off. Hence, water infiltration to the roots is increased and erosion prevented. 

Plant Cover

Grass

10-15 cm

Grass roots

10-15 cm

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Manual of techniques for sustainable mountain viticultur

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The growth of plant cover using quick grass may be developed in two ways: 

•

Plant the appropriate quick grass (reproduction using tufts and shallow roots so that it only com-

petes for the surface moisture of the soil, which is extremely ephemeral and has less impact on

the vine). 

•

Cut other spontaneous grass before flowering so that it cannot reproduce and allow the quick

grass to colonise the soil. 

Moreover, it has been seen that working on terraces with a single outside row of stock ends up lowe-

ring the inside of the upper slope. The ploughed land is accumulated on the inside of the terrace and

may even change the direction of the sideways slope of the terraces, which would lead to the length-

ways draining system breaking up and a serious risk to the stability of the entire terracing. 

Quick grass

Plant cover being formed

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3.7.2 Control of disease and blight

The risk to the vine is primarily concentrated into three diseases caused by fungus:

•

Oidium (Cendrosa): The most important damage is located on the roots, as strong attacks cause

the skin to stop growing, making the fruit crack and tear. Shoots also wither and the penetration

of grey mould (Botrytis cinerea) is favoured.

•

Mildew: This is one of the most famous and most serious diseases, as if the weather conditions

are favourable, it can attack all the green organs of the vine to cause losses of up to 50% or more

of the harvest. 

•

Botrytis (grey mould): This is seen on herbaceous organs (leaves, shoots and flower fruits), on

cuttings-grafts in warm stratification chamber and primarily on bunches.

In general, three strategies can be applied for controlling these diseases: 

•

Systematic application of phytosanitary productions at several times during the vegetative cycle of

the vine, independent to the external risk. The same applications are repeated every year. 

•

Collective model: The application of phytosanitary products follows the instructions of a wine pro-

ducing district body created by local governments or by farming associations. These bodies base

their recommendations on general risk assessment models that are fed on data from the weather

stations located in the district. 

•

Specific model: Each vineyard provides a set of specific data from its own estate for an interacti-

ve risk assessment model that provides results that are more closely adapted to the situation of

the estate. 

This latter strategy has been experimented, applying a specific model from Holland. The following

information must be added frequently to the model: 

- Plant growth speed.

- Vegetative state (current time of the cycle).

- Grape variety (more or less sensitive).

- Level of plant densification or compacting.

- Weather data regarding the estate. It is therefore wise to install a weather station on the vineyard.

- Historic weather data from the closest or most representative station.

- Specific conditions of the estate (presence of a disease or blight on a neighbouring vineyard, stock

affected on the vineyard itself, etc.).

Weather station on the vineyard

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Manual of techniques for sustainable mountain viticultur

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Fungicides for the control of vine disease

The main diseases attacking vines are caused by phytopathogenic fungi. Fungicides used to con-

trol these diseases can be classified in three groups, according to the way they act with regards

to the plant:

- Contact: these act on the green organs entering in contact with the product. They are used in a

preventative manner, i.e. to prevent the disease from taking hold of the plant. Once the disease

has taken hold, they are no longer of use to eliminate it (they are not curative). Rainfall of over

10 l/m

2

washes the product away and the plant becomes unprotected. Another disadvantage

is that their action is limited to the treated organs (those with which they come into contact)

and those forming after the treatment are unprotected. 

- Penetrating: as their name indicates, they penetrate the treated organs and are, therefore, not

washed away by rain. Their effects are preventative and curative (once the disease has affected

the plant). They do not protect untreated parts.

- Systemic: these penetrate the inside of the tissue and are transported by the sap, thus also

protecting shoots formed after application. They are essentially curative and are not washed

away by the rain.

Preventative contact fungicides based on copper and sulphur compounds are the most com-

monly used. They are also the most environment-friendly, as the main ingredients exist in nature.

Penetrating and systemic fungicides are synthetic and, therefore, are foreign to the environment.

If used, they must be alternated so that fungi do not become resistant.

The model returns the risk to which the vineyard is subjected for the different diseases. If the risk exceeds

a certain threshold, a preventative treatment must be applied. If the correct action is not taken, the

model sends another warning and the application of a curative pesticide may then be recommended,

normally of a higher toxicity than the preventative application.

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