Use of sulphur in agriculture
Sulphur is a chemical element with atomic number 16 and symbol S. It is located in the periodic table within the group of non-metals, has a yellow color and is quite abundant in volcanic areas of the Earth. As a chemical element is essential because it is part of amino acids such as cysteine and methionine, necessary for the synthesis of proteins present in all living organisms.
The use of sulphur as a fungicide began in approximately 150 A.D. However, the use of sulphur as a fungicide became an agricultural practice between 1845 and 1847 in England and France for the control of powdery mildew in vineyards (Paul, 1978). In 1974 the implementation of elemental sulphur was successfully used in the control of fungi in beet cultivation in the USA1.
Sulphur plays an important role in the defense mechanisms of plants against pests and diseases. Plants contain a diversity of secondary metabolites and many of them have sulphur in their structure. These compounds can be in active form or as inactive precursors, the latter being activated by the action of enzymes when there is an attack of a pathogen or when tissues are mechanically damaged1.
It can act by direct contact and at a distance, the latter thanks to the gaseous compounds it produces. It is used against fungi, mainly from the ascomycetes class such as oidium. In addition, it is able to stop the infection of the fungus, at least in some phases of its biological cycle. On the other hand, it is also used for the control of mites and some thrips, especially in the early larval stages. In viticulture it is usually applied in powder form since the bunch is green and the danger of powdery mildew is serious. In fruit trees and vegetables can be applied throughout the crop cycle. It is advisable not to apply sulphur in seasons with high temperatures because it loses much efficiency and persistence is reduced by rapid evaporation. It can be applied in mixture with copper compounds, obtaining a double action against mildew and odios.
By Andrés Borges.