Xanthomonas campestris pv. vesicatoria [Xanthomonas vesicatoria] is the causal agent of bacterial spot of tomato and pepper. The disease causes significant loss, particularly in warm and humid environments. Although it is spread in Europe, it is listed on A2 quarantine list. In the northern European countries, tomato and pepper are grown only in glasshouses. Bacterial spot develops on seedlings and mature plants. In seedlings, infections may cause severe defoliation. In older plants, spots occur on leaves, stem and fruits. Besides bacterial spot, which is listed on A2 in Slovenia, tomato can also be infected with two other bacteria, which are impossible to distinguish based on symptoms: Clavibacter michiganensis pv. michiganensis [C. michiganensis subsp. michiganensis] (EU list A2) and Pseudomonas syringae pv. tomato (harmful organism). In Slovenia, bacterial spot was first identified by laboratory methods in 1999, on pepper plants, grown in the Nova gorica and Kostanjevica regions. Bacteria were isolated from plants with symptoms on common media: NGA, King's B, Yeast extract-dextrose-CaCO₃ and selective Tween B medium. Serologically, it was identified by immunofluorescence. Identification was confirmed in the Central Science Laboratory in York, Great Britain (UK), with the analysis of the fatty acid profile. The bacterium persists from one season to the next in crop debris or on weed hosts. It is seedborne, particularly in tomato, the incidence in seeds was as high as 60%. The most efficient control methods are the use of healthy seeds, heat treatment or chemical sterilization of seeds, or the use of resistant cultivars. Bactericides with copper can be applied, although it is important to establish whether selected isolates carry resistance against copper, which can vary and is related with the presence of a 200 kb plasmid.