Phylloxéra - SpeedyLook encyclopedia

Description

Will phylloxéra is a tiny insect pledged stitcher with the vine, related with the plant louses, equipped with a remarkable polymorphism:

the parthenogenetic forms, females which reproduce by Parthénogenèse - without intervention of males -, are apterous - deprived of wings -, of color going of the yellow to brown, a size varying from 0,3 to 1,4 mm; one distinguishes:

the gallicoles forms, which live on the Feuille S;
the radicicolous forms, which live on the root S;

the sexuées forms, which do not feed, are deprived of parts Buccal are:

female winged, gold yellow with ocher, the transparent wings, measuring from 2 to 3 apterous mm,
male, length from 0,3 to 0,5 Misters

The biological cycle of will phylloxéra

The male and female insects couple themselves at the end of the be. The female lays on the stocks a single egg called egg of winter . This egg, initially yellow, then green during the season of Winter, hatches with the Printemps and gives rise to the will phylloxéra apterous (or without wings ), which is always a female. In the majority of the cases, this will phylloxéra apterous goes down on the roots of the vine, at the expense which he lives, from where its name of will phylloxéra radicicolous ; but it can sometimes go on the Feuille S, giving birth to from the Galle S (one speaks then about will pylloxéra gallicole ).

Will phylloxéra radicicolous is yellow. It is provided one to suçoir which it inserts in the root to absorb the Sève of it. It, or rather it, undergoes three driven in a score of days, before becoming adult and starting to lay between 40 and 100 eggs, giving all, them also, birth with females. This twenty days cycle reproduces on several occasions, giving in all five or six generations.

In summer, all these females undergo a moult moreover and transform themselves into nymph S , which will become themselves of the will phylloxéras winged . These will phylloxéras winged lay again (on the bud S and the sheets of the vines), their eggs giving this time birth to males and females. The latter live only a few days, just time to couple and produce egg of winter mentioned above.

The damage caused with the vine

The infestation of a vine stock by will phylloxéra results in its death in three years. In fact the radicicolous generations - live on the root S - which are dangerous. Their punctures on the young roots cause the formation of Tubérosité S, which, thereafter, infect and precipitate the death of the foot. The gallicoles generations - which live on the Feuille S on which their punctures cause the formation of Galle S - involve a yellowing of the Feuillage, which is not mortal for the plant.

Chronology of the invasion of will phylloxéra in Europe and in the Monde

Will phylloxéra was initially established in France. The first hearths of infestation which appear here or there are due to the imprudence of Pépiniériste S or experimenters; then the infestation extends in spot from oil more or less quickly according to the density of the vineyards and the influence of the dominant winds. In spite of the measurements imposed by the States to control the imports of stocks, will phylloxéra it gradually infested the vineyards of the whole world, saving only the vineyards planted out of sandy ground, and the resistant American seedlings.

1863 : first appearance of will phylloxéra with Pujaut in the Gard (France) and in a greenhouse (where it will be controlled) with Hammersmith, close to London (Great Britain);
1865: second hearth of infestation in Crau-Saint-Rémy Rhone delta;
1865: first infestation with the Portugal (valley of the Douro);
1866: new hearth with Floirac in the Gironde;
1868: identification by Planchon of the plant louse devastator, already identified with the the United States in 1854 by Asa Fitch under the name of Pemphigus vitifoliae ;
1871: the zone infested in the valley of the the Rhone form a large triangle which reaches Cadarache in the East, Castries in the West and Silvering-the Hermitage in North;
1871: first Swiss hearth in , close to Geneva;
1872: new hearth in France close to Cognac;
1873: will phylloxéra appears in California;
1874: first appearance in Germany close to Bonn;
1876: new hearth of infestation with Orleans;
1875: will phylloxéra extends to the Austria;
1875: the Australia is contaminated;
1877: first appearances in Spain with Malaga (Andalusia) and Gérone (Catalonia);
1878: extension of will phylloxéra in Coast-with Or;
1879: discovered will phylloxéra in Italy, with Valmadrera, close to Like;
1880: two new Italian hearths with Caltanissetta (Sicily) and Imperia (Genoa);
1880: The South Africa is touched;
1885: first appearance in Algeria with Mansourah, close to Tlemcen;
1886: new hearth in Algeria, with Philippeville (today Skikda);
1888: will phylloxéra reached the Peru;
1894: the vineyard of the Champagne is reached;
1905: extension to the Tunisia;
1914: the Mandchourie is reached;
1919: the Morocco is reached;
1980: the area of Tokat in Turkey is reached (type of vine Narince " frankly of pieds")

Means of fight used

Wine growers and scientists initially were completely disarmed in front of the disasters caused by the insect. The experiment quickly proved that the vines planted in sandy ground resisted will phylloxéra (sand, by its structure and its mobility, preventing by crushing the radicicolous forms from going down towards the roots), but one could with difficulty plan to transplant all the sandy ground vineyard. One thus tested, often in an empirical way, the various treatments the more or less happy results:

White-washing of the stocks, in order to destroy the egg winter, with a mixture of water, Quicklime, Naphthalene rough and heavy oil of coal. Still practiced at the beginning of the XXe century, this technique did not prove very effective.
Treatment by the Carbon bisulphide: one introduces into the ground, using special apparatuses, a certain quantity of carbon bisulphide, liquidates very volatile whose vapors will kill the insect. The product was injected into the ground using a sulfurous Charrue or of an injecting stake (stake Vermorel). The method was rather effective, but too long and too expensive, just like the treatment by the Sulfocarbonate of potassium, which consisted in digging a basin around the stock and pouring a liquid solution there.
Treatment by immersion: one drowns the vineyard under a layer of water which will asphyxiate the insect. Excellent method certainly, but being able to apply only to the irrigable grounds , in other words least favourable with the vineyards of quality.

Plantation of American vines, which one had realized that they were immunized against will phylloxéra.

This last method was not easily possible, because it would have led to the loss of all the Cépage S French of quality. But it contained in germ the good solution: to use the American seedlings as understocks, technique always used today to secure itself will phylloxéra.

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