The present invention relates to an agricultural composition and the uses thereof to protect crops against attack by plant pathogens and/or to improve the resistance of crops to infections caused by said pathogenic agents and/or to enhance the tolerance thereof to abiotic stresses, such as those caused by cold, salinity and drought. Said composition comprises an association of an at least partially depolymerized chitosan with a bivalent copper chelate. The composition has shown to be particularly suitable-for treating oidium infections. It is moreover useful against the propagation of viruses and/or particularly effective as a biostimulant to plant and fruit growth and/or able to extend the shelf life of fruit and seeds.
