The phloem-restricted phytopathogenic bacterium Candidatus Arsenophonus phytopathogenicus (Ap) causes the “syndrome basses richesses” (SBR), which has recently emerged as a major burden for sugar beets in several countries of Western Europe. Here, we report the first identification of Ap and its planthopper vector Pentastiridius leporinus in potato fields in Switzerland in 2023. The bacterium was detected in potato plants and...