(EN) The invention concerns a method for potentiating and stimulating the natural control system of agriculturally useful plants, using a phytosanitary composition containing one or several oligo beta 1-3 glucans consisting of 3 to 250, preferably, 3 to 50 and more preferably 3 to 30 carbohydrate units, the oligo beta 1-3 glucan concentration characteristics and the use of this composition being selected such that it brings per cultivated hectare an amount of oligo beta 1-3 glucans less than the amount which directly induces the natural control reactions, said amount ranging in practice from 1 to 200 g, preferably 4 to 80 g per hectare in the case of cereals and in particular of wheat.
(FR) L'invention a pour objet un procédé de stimulation des défenses naturelles de plantes agronomiquement utiles, caractérisé par le fait qu'il comprend l'application notamment foliaire, auxdites plantes d'une quantité efficace d'au moins un oligo 1-3 glucane, ainsi qu'une composition pour la mise en oeuvre de ce procédé.