The present invention relates to the use of dithiine-tetracarboximides of formula (I) for controlling selected bacterial harmful organisms in useful plants, wherein the bacterial harmful organisms are selected from the group consisting of Acidovorax avenae, Burkholderia spec., Burkholderia glumae, Candidatus Liberibacter spec., Candidatus Liberibacter asiaticus, Corynebacterium, Erwinia spec. (Dickeya, Pectobacterium carotovorum, Erwinia amylovora), Pseudomonas syringae, Pseudomonas syringae pv. actinidae, Pseudomonas syringae pv. glycinea, Pseudomonas syringae pv. tomato, Pseudomonas syringae pv. lachrymans, Pseudomonas tumefaciens (=Agrobacterium tumefaciens), Streptomyces spp., Xanthomonas spp., Xanthomonas ampelina, Xanthomonas axonopodis, Xanthomonas axonopodis pv. citri, Xanthomonas axonopodis pv. glycines, Xanthomonas campestris, Xanthomonas campestris pv. musacearum, Xanthomonas campestris pv. pruni, Xanthomonas campestris pv. Viticola, Xanthomonas fragariae and Xanthomonas transluscens or Xylella fastidiosa. The present invention also relates to a method for controlling the selected bacterial harmful organisms in useful plants by treatment with a dithiine-tetracarboximides of formula (I).