Plant diseases

Downy mildew of the vine

The vine in Italy

The vine is one of the most important plants both from a historical and an economic point of view in Italy; in fact it is the protagonist of a cultural tradition that started millennia ago with the ancient Greeks, who both in the Greek motherland and in the numerous and flourishing Italic colonies loved to drink wine at every meal and praised its characteristics. everything then continued with the ancient Romans, who elected wine to “god” and used it several times during the day. everything has come down to us, who, capable of managing and exploiting the enormous natural resources we have, have made wine a symbolic product of “made in Italy” worldwide, with various acronyms that protect our regional products and even local, with some of these being ordered on the other side of the world, where they await their arrival for months and months and pay their weight in gold. The wine and viticultural industry brings Italy several billion euros a year, thus fueling a big business and above all giving work to many people. In fact, a fundamental role that we will talk about today is that of the one who takes care of the plants, to make them survive and perform at their best.

Downy mildew of the vine


The technician who deals with the diseases, infections and infestations of the vine plant must beware of various sworn enemies of this great plant; one of these, which happened “by mistake” in our area is the downy mildew of the vine: this is a microorganism whose scientific name is “Plasmopara viticola”, which makes us understand very well the link it has with the vine and its whole world . Originally ascribed to the kingdom of the Mushrooms, in 1985 this species was moved to the kingdom of the Chromists, born later and therefore for this reason supplied from time to time with other species. Indeed, the fact that this downy mildew (a name which among other things is not exact, indicating the first, marginal, noted characteristics of this species) was previously considered a fungus is plausible, since it comes in two forms, both of which can be judged as fungi: one is the wildfire form and is the manifestation of the primary infection of the disease, while the other is the white mold form, manifestation of the secondary infection of the same species. Studies have not yet concluded with certainty whether it is always two related infections or not, but it is certain that the presentation of each is linked to the climatic regime it encounters.

Effects of downy mildew

Downy mildew, of which we have briefly seen the two forms and a sort of history, is not native to our areas, but rather to the American continent; since it does not fly, and certainly would not cover the thousands of kilometers that separate us from the American continent on the Atlantic Ocean, we tried to understand how it reached the European continent. It turned out that it happened towards the end of the eighteenth century, when it accidentally arrived in France on a cargo from South America and from there it spread throughout Europe, becoming one of the most feared diseases by vine growers. The effects of this disease can be seen on the leaves, with the white mold or the oil spots already mentioned above, but above all they can be seen on the bunches of grapes, which take on the classic dried S shape and fall prematurely;

Fight against downy mildew

The fight against downy mildew is a very current topic because it is essential for every grape producer to fight this disease; Well, historically, the fight against downy mildew is carried out with copper-based treatments, such as the Bordeaux mixture so famous and known above all by our grandparents. Copper is the only active ingredient accepted in organic crops, but it has various defects: first of all it is a preventive and not a healing cure, therefore it serves to prevent the disease but if it is already present it cannot heal it, but then an accumulation in the soil ( since the treatment must be repeated after each rain because it is washed away) causes pollution and problems to the roots and to the development of the plants. Since the end of the Second World War, various agents have been studied against downy mildew and many of them have been found to be quite effective even in the healing part, without even being very toxic for humans and the plant itself, however their problem is that excessive use they can lead the microorganism to develop a defense and a habit of the active principle, which would make it unassailable, therefore it must not be excessively used (also because it resists even intense rains). Incidentally, this problem does not arise with copper, the action of which the microorganism will never get used to or counter in any way (its limit is only the pollution it causes in the soil). their problem, however, is that excessive use can lead the microorganism to develop a defense and a habit of the active principle, which would make it unassailable, so it must not be excessively used (also because it resists even intense rains). Incidentally, this problem does not arise with copper, the action of which the microorganism will never get used to or counter in any way (its limit is only the pollution it causes in the soil). their problem, however, is that excessive use can lead the microorganism to develop a defense and a habit of the active principle, which would make it unassailable, so it must not be excessively used (also because it resists even intense rains). Incidentally, this problem does not arise with copper, the action of which the microorganism will never get used to or counter in any way (its limit is only the pollution it causes in the soil).

Related posts

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *

Botón volver arriba