A method for combating bacterial infections in plants including the step of applying a plant protection agent onto the blossoms and/or leaves of the plants. The plant protection agent includes a compound according to formula (A) or formula (B), where R1, R4 and R5 are H, a glycoside, or an ester independently of each other, and the compound is dissolved in a solvent at a concentration of 0.1 μM to 2 mM.
