Brooms were used to coat vines with sulphur in the fight against downy mildew
Downy mildew attacked vines towards the end of the 19th century. The canton in Valais gave the alarm in 1892. Growers who do not put up a fight against the new diseases will lose their vines. A weapon arrives to neutralize this parasite fungus, a blue preparation made with copper: the Bordeaux mixture.
This magic potion was discovered by accident, in France. In the Medoc, growers noticed that leafs covered with verdigris to keep away thieves were spared downy mildew. In the area around Beaune, in Burgundy, vines near stakes treated with copper sulphate remained healthy.
The first mixture, ready to be applied, was called La Renommée and could be bought at the village food store. Today it has been replaced by synthetic products, but some growers still use it, alternating it with other fungicides.
In the early days, it was applied manually with the help of a natural broom made of straw or a branch of Swiss pine (also called Arolla pine) or juniper, soaked in a bucket or pail with the mixture. The first spray versions came into use in the 1870s and the first pumps for sulphating were sold in 1888. During the 1960s a motorized sprayer appeared. From the first pumps adapted for motorized cultivation, to motorized pumps and turbo-sprayers, to helicopter sprayers: the methods for spraying these treatments have continually improved, with gains in efficiency, time and manual labour.
Source: Histoire de la Vigne et du Vin en Valais, «Maladies et ravageurs: plus d’un siècle de lutte», by Mélanie Duc, ethnologist and Augustin Schmid, biologist.