Powdery mildew or Oidium Tuckeri, also known as "ashtray" or "powdery mildew", is a fungus that originated in North America and was first identified by an English gardener in 1845. This fungus invaded European vineyards in 1851, causing major losses, including in the Douro region. Treatment with powdered sulphur was identified by Frenchman Henri Marès in 1853. Since then, this natural fungicide has been used regularly in vineyards, two or three times a year. As it is not preventative, it can only be applied after the first signs have appeared, which is why many vineyards have rows planted with roses, a plant that is very sensitive to the presence of the fungus.
Historically, according to Moreira da Fonseca, the first grafting is carried out shortly after the vine shoots, when the shoots are 0.10 cm to 0.15 cm tall; this is known as the "shoveling of the shoots". The second is carried out at the time of flowering - enxofra do florir, when the flower is peeled, which happens in May or early June. Finally, the third swathe is a "check" before the grapes turn color. If powdery mildew persists, it is repeated as long as necessary in the affected areas, even swabbing the bunch.
For this new agricultural work, different tools were developed that allowed the sulphur to be dispersed more or less locally, known as sulphur spreaders in general, but which, due to their different shapes, took on different names, such as the torpille. Its name comes from the French torpille - torpedo, certainly associated with the particular shape of this device first marketed by Vermorel, as Afonso do Vale Pereira Cabral points out.
Given the device's success, it was copied by Portuguese factories and tinsmiths, giving rise to a variety of models that lasted over time, such as the Aurita model from Casa Hipólito in Torres Vedras.
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