A use of a compound corresponding to the following formula: Si(CH 3) 3-n n wherein X is a hydrogen atom or an alkali metal, in particular selected from lithium, sodium or potassium and n is an integer ranging from 1 to 3, for a foliar application to crops, said crops being in particular selected from the group comprising: - field crops, in particular those selected from cereals, oilseeds, protein crops, fodder legumes, fodder grasses or sugar crops, - vegetable or market garden crops, in particular fresh vegetables, - fruit crops, in particular those selected from stone fruits, pome fruits, almond fruits, cluster fruits, small fruits or fruits of warm regions, - aromatic and medicinal plants - floral and ornamental crops, and mixtures thereof, and for its specific action on the metabolism of crops, namely to: - improve the growth and development of the crops, - improve the yield of the crops, - stimulate and strengthen the crops in the face of biotic stress, in particular by improving their resistance to phytopathogenic agents and/or pests, and/or - improve the health quality of the crops, namely in particular reduce the level of mycotoxins and limit the protein dilution, said compound being in liquid form and being used in an amount ranging from 10 -5 L to 1 L per hectare of crop, preferably from 2×10 -5 L to 0.2 L per hectare of crop, and more preferably from 4×10 -5 L to 4×10 -3 L per hectare of crop. wherein X is a hydrogen atom or an alkali metal, in particular selected from lithium, sodium or potassium and n is an integer ranging from 1 to 3, for a foliar application to crops, said crops being in particular selected from the group comprising: - field crops, in particular those selected from cereals, oilseeds, protein crops, fodder legumes, fodder grasses or sugar crops, - vegetable or market garden crops, in particular fresh vegetables, - fruit crops, in particular those selected from stone fruits, pome fruits, almond fruits, cluster fruits, small fruits or fruits of warm regions, - aromatic and medicinal plants - floral and ornamental crops, - field crops, in particular those selected from cereals, oilseeds, protein crops, fodder legumes, fodder grasses or sugar crops, - vegetable or market garden crops, in particular fresh vegetables, - fruit crops, in particular those selected from stone fruits, pome fruits, almond fruits, cluster fruits, small fruits or fruits of warm regions, - aromatic and medicinal plants - floral and ornamental crops, and mixtures thereof, and for its specific action on the metabolism of crops, namely to: - improve the growth and development of the crops, - improve the yield of the crops, - stimulate and strengthen the crops in the face of biotic stress, in particular by improving their resistance to phytopathogenic agents and/or pests, and/or - improve the health quality of the crops, namely in particular reduce the level of mycotoxins and limit the protein dilution, - improve the growth and development of the crops, - improve the yield of the crops, - stimulate and strengthen the crops in the face of biotic stress, in particular by improving their resistance to phytopathogenic agents and/or pests, and/or - improve the health quality of the crops, namely in particular reduce the level of mycotoxins and limit the protein dilution, said compound being in liquid form and being used in an amount ranging from 10 -5 L to 1 L per hectare of crop, preferably from 2×10 -5 L to 0.2 L per hectare of crop, and more preferably from 4×10 -5 L to 4×10 -3 L per hectare of crop.