Index
1- Vine Downy, (Plasmopara viticola Berl. And Toni) Vine diseases.
2- What is Vine Mildew?
Vine mildew is one of the best known and most serious vine diseases in viticulture, since if the environmental conditions are favorable, it can attack all the green organs of the vine plant, being able to lose an important part of the production from grape.
It is a fungus and its activity begins in spring, when its development conditions are favorable.
The click of the fungus will be repeated over and over again depending on the humidity, until in autumn, the fungus will enter the resting phase again.
The following conditions are ideal for fungus activity :
· Shoot length of 10 cm or more.
· Fall of a rain of 10 mm minimum.
· Average temperature above 10ºC.
3- Sinonimias del mildiu en vid
Grapevine downy mildew is also known as: mildew, mildew, fog, blight.
4- Influence of weather conditions for the development of vine mildew.
Climatic factors have a total influence on the development of this fungus.
There is a rule to remember which are the favorable conditions for the development of the disease, known by the three 10, and that is, that the disease develops when the 3 * 10 are fulfilled:
- Buds on the vine equal to or greater than 10 cm.
- Precipitation greater than 10 mm or 10 L / m2.
- Average temperature above 10ºC.
If we are in the period of development of the disease, and these three conditions occur, preventive treatment must be carried out .
This disease appears in regions of hot and humid climate during the vegetative growth period.
The conditions of propagation of this fungus are high relative humidity and temperature.
The conditions of propagation of this fungus are high relative humidity and temperature.
With relative humidity greater than 75% and temperatures between 12 and 30ºC, the daily development is greater than 25%.
5- Symptoms and damage of mildew in vineyard.
· In sheets.
The typical oil stains can be distinguished on the upper surface, corresponding to a whitish fluff on the underside.
· Shoots and shoots.
The shoots are curled, covered with a whitish fluff, which can dry out and fall if the attack is strong.
· Milded in Cluster.
The grains can be attacked initially or later. In late attacks, the clusters are not covered with a white fluff but they acquire a brown color.
6- Ecological treatment. Preventive-cultural measures against grapevine mildew.
The preventive measures will be all those that favor the ventilation and aeration of our vineyard.
- Carry out the plantations in the direction of the prevailing wind .
- Proper management of vegetation , with tips or pruning in green (better pruning in green than topping).
- Thinning of leaves affected or with symptoms of downy mildew on vine to reduce inoculum.
- Control nitrogen fertilizer , and avoid excesses.
- Planting of vine varieties less susceptible and more resistant to the disease.
7- Mildew treatment: Chemical control of vine mildew.
Recommended fungicides against mildew:
The chemical control of downy mildew vineyard be performed when weather conditions are favoring development of the disease.
The protection strategy consists of treating in a timely manner to prevent the development of the disease.
In situations with a humid atmosphere and prone to mists and dews, the conditions for the development of mildew are ideal, which is why several treatments are necessary.
There are three types of chemicals on the market for treating vine mildew.
– Contact products against vine mildew:
- This type of product is usually used in preventive treatments of mildew on the vine, since they are effective while they are on the plant.
- They do not penetrate the interior of the plant , and can be washed away by rain. No resistance is created.
- They are effective for 4 to 8 days and treatment can be repeated, especially when it rains or when there is very rapid growth.
- Some active contact materials are: captan, folpet, cupric hydroxide, mancozeb, maneb, metiram, copper oxychloride, cuprous oxide, curpcalcium sulfate and tolifluanide.
– Penetrating products for vineyard mildew treatment :
- This type of product partially penetrates the interior of the plant but does not move more than a little in the area where they have been applied.
- They are preventive but also curative products in the first days of vine mildew disease.
- They are effective for 8 to 10 days.
- They generate resistance. They should not be done more than 3 or 4 treatments in a row a year.
- Penetrants include: azozistrobin, cymoxanil, dimethomorph or famoxadone.
– Systemic Products against grapevine mildew:
- In this type of product, the product penetrates inside the plant and circulates through the sap to all organs.
- They are preventive but also curative phytosanitary products in the first days of vine mildew disease, protecting the new organs formed by the growth of the plant after treatment.
- The duration is around 12 to 14 days.
- They generate resistance, so treatments must be limited.
- Among the systemic products we have benalaxil, fosetyl-al, iprovalicarb, melaxil M or metalaxil.
8- Mildew cycle of the vine
Downy mildew is an endoparasitic fungus that gets into the spaces between cells in all parts of the vineyard.
It winters without showing activity in the strain, plant debris, in the soil, in the form of an egg known as an oospore . At the arrival of spring and when the right conditions are met, its activity begins.
The stages of the mildew cycle are as follows:
- Contamination : it is the first stage that the oospores finish the winter lethargy and germinate.
- Incubation : it spreads intercellularly, the first typical oil spots appearing on the underside of the leaves.
- Sporulation : in this phase the sexual multiplication of cells occurs during almost the entire vegetative period of the vine.
- Propagation : final stage in which zoospores spread through secondary contaminations to perpetuate the species. Pag through rain or air breezes is common
9- Active substances against vine mildew :
Vineyard phytosanitary products registered for mildew. The Registry may vary as it is periodically updated and new products are always coming out.
The most used are the following:
- AZOXISTROBIN
- BENALAXIL
- BENTIAVALICARB ISOPROPIL
- CIAZOPHAMIDE
- CIMOXANILO
- DIMETOMORF
- FAMOXADONA
- FLUOPICOLIDA
- FOLPET
- FOSETIL-AL
- HIDROXIDO CUPRICO
- MANCOZEB
- MANEB
- METALAXIL
- METIRAM
- COPPER OXYCHLORIDE
- CUPROSE OXIDE
- PIRACLOSTROBIN
- SULFATO CUPROCALCICO
- TRIBASIC COPPER SULPHATE
