Chitosan in induced resistance: more chances than limits or vice versa?

Abstract: The effectiveness of chitosans (CHTs), deacetylated chitin derivatives, as plantresistance inducers depends on a number of variables, such as the molecular weight (MW) and thedeacetylation degree (DD) of the oligomers/polymers, the solvent, the pathosystem and the modeof administration. All these aspects are briefly examined and discussed with the aim of givinguseful advices for succesfull application of CHTs, particularly to control virus diseases.