The present invention relates to a method for the control and the treatment of post-harvest diseases in fruits and vegetables by means of simultaneous and combined application of (i) a first formulation, which is aqueous or in the form of an emulsifiable concentrate, which comprises a plant extract and is applied in the form of an aqueous solution and (ii) a second formulation, in the form of an emulsifiable concentrate, soluble liquid or concentrated suspension, which is applied as an aqueous solution, selected from amongst: a plant-strengthening formulation that contains at least one phosphite salt; a fungicidal formulation that contains at least one synthetic fungicide of the phosphonate family, preferably ethyl phosphonic acid salts; or a combination thereof. Each formulation may be a different composition or form part of a single composition. A further subject matter of the present invention is therefore said composition for post-harvest protection of fruits and vegetables which is constituted by the combination of the aforementioned components.