The invention relates to a method for stimulating the natural defence and the induction of resistance to diseases in plants, by means of the simultaneous activation of genes related to the pathway of salicylic acid, to the pathway of jasmonic/ethylene acid and to the hypersensitivity response. The invention also relates to the use of brassinosteroids for the preventive and curative treatment of the plants, against diseases caused by pathogens. The invention further relates to a method for preventing and treating the disease Huanglongbing in citrus fruits.
