Sulfur powder

His own story

Nine centuries before Christ, Homer mentioned sulfur which in Greece was used as a fungicide. Together with coal and potassium nitrate it was one of the components of the gunpowder invented by the Chinese in the 12th century. Alchemists depicted it with a triangle above a cross and learned that it could combine with mercury. Later Lavoisier proved, with his experiments, that sulfur is an element and not a compound. In Italy, sulfur was extracted in Sicily: from the mid-18th century and in the second decade of the 1800s the country supplied 4/5 of the entire planetary production, exporting it throughout Europe and even overseas, to America. With the discovery of their fields and the introduction of the Frasch process, the Americans, however, conquered world markets in turn.

The sulfur

It is light, soft, odorless, but when it binds with hydrogen it forms hydrogen sulfide, and it smells like rotten eggs. If it burns it makes a bluish flame and has a peculiar smell; it cannot be dissolved in water. In nature it is found mainly to form sulphides and sulphates, but also within oil and coal, albeit to a modest extent. Calcium polysulphide is an insecticide used against scale insects in orchards; the sulphate forms (potassium, for example) are used as fertilizer. It is obtained by extraction, from fossil fuels and from mines, using the Frash method which involves the introduction, inside the reservoir, of a mixture of hot water vapor and compressed air. The sulfur, melted by the high temperature, reaches the surface pushed by the pressure.

Sulfur powder

Powdered sulfur is presented as a dry powder, to be distributed as it is to plants. The market offers different types: activated sulfur which is obtained by mixing sulfur and carbon black from vegetable fats, has a more pronounced action. The ventilated sulfur, prepared by milling and the subsequent separation of fine particles with ventilation; followed by refined (or sublimed) sulfur, a very effective type of sulfur which is obtained with a process of condensation of the vapors coming from the distillation of sulfur. Finally, the raw sulfur, which contains a rather low percentage of sulfur, is obtained by milling. It should be noted that the legislation on organic farming allows the use of plant protection products that contain sulfur inside.

Powdered Sulfur: Use of powdered sulfur

Powdered sulfur has a good ability both to prevent and to fight against Oidium or white disease. Collaterally it also has an inhibitory activity against mites, such as eriofidi and red spider mites. It acts in the gaseous state that occurs most intensely at high temperatures and on the basis of the particle size. Basically, the hotter it is, the finer the sulfur and the greater its action. It begins its effects on 10-12 ° C. below which, however, it is scarcely effective. We must be careful at high temperatures: above 30-32 ° C it becomes phytotoxic, therefore in summer it is better to intervene on the plants by spraying them in the coolest hours of the day. Relative humidity is an inhibiting factor on its action. The waiting time varies from 3 to 15 days, depending on the formulation.

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