In order to replace methyl bromide in all the uses thereof in soil or substrate treatment, the invention relates to the use of at least one sulphur compound having general formula: wherein R represents an alkenyl or alkyl radical, n is equal to 0, 1 or 2, x is a number between 0 and 4 and R′ represents an alkenyl or alkyl radical or, only if n=x=0, a hydrogen or alkali-metal atom. The sulphur compounds (in particular dimethyldisulphide) can be applied according to standard soil treatment methods (by injection, spraying, dripping, sprinkling) and said compounds have no phototoxic effects.