Ralstonia solanacearum species complex (RSSC) is one of the most devastating bacterial plant pathogens causing bacterial wilt in a wide range of hosts including crops and wild plants. These soil-borne Gram-negative bacteria have a worldwide geographic distribution and significantly reduce crop yields especially in tropical regions such as the southwestern Indian Ocean. Due to the lack of efficient curative measures and the high persistence of RSSC, phage therapy represents a sustainable plant disease management strategy to be applied in agricultural settings. However, using phages as a biocontrol tool raises concerns about the potential of phage resistance evolution in plant pathogenic bacterial populations. To explore this question, we first evaluated the in vitro virulence of a local phage collection against the most prevalent strain of RSSC in Reunion Island. Then, we examined the temporal adaptation of the strain to these phages, and its consequences for bacterial fitness. Analysis of the virulence of the 10 phages tested showed that they were all able to effectively reduce bacterial growth. The emergence of bacterial resistance was reported after two or three days. Absence of clear lysis plaques were observed in evolved bacteria not only against the phage encountered but also against the entire phage collection, which included several phage species and genera. These results show high cross-resistance emergence, which resulted in a fitness cost for the bacteria, as measured by a reduction in growth rate and loss of swimming ability for 8 of 10 evolved bacteria exposed to the different phages. These results suggest that phylogenetically distant phages can be rapidly blocked in bacteria. Mechanistically different phages or complementary strategies may be needed to efficiently control phytopathogens. Conversely, fitness costs in bacteria point in the direction of a reduced virulence in planta. Further in vivo and genetic analysis will bring light to these questions.