LAUSR

Simple Summary Pentastiridius leporinus is a planthopper that transmits two bacterial pathogens to sugar beet plants: Arsenophonus and Stolbur. These bacteria cause an economically important disease known as syndrome basses richesses (SBR), characterized by deformed yellow leaves and low beet yields. Having observed potato fields in Germany infested with planthoppers and showing signs of leaf yellowing, we set out to identify the planthoppers and any transmitted pathogens. We identified P. leporinus by comparisons of COI and COII partial sequences and detected both bacterial pathogens in planthoppers, as well as in beet and potato plants. We found that P. leporinus nymphs and adults can transmit the bacteria and that long, warm summers allow two generations of planthoppers to breed, probably increasing the population size and threat of disease transmission in the following year. We conclude that the planthopper P. leporinus has expanded its host range to potato, and that further studies are needed, to facilitate the development of control strategies that minimize losses in sugar beet and potato crops. Abstract Pentastiridius leporinus is a planthopper (Hemiptera: Cixiidae) that vectors two phloem-restricted bacterial pathogens to sugar beet (Beta vulgaris (L.)): the γ-proteobacterium Candidatus Arsenophonus phytopathogenicus and the stolbur phytoplasma Candidatus Phytoplasma solani. These bacteria cause an economically important disease known as syndrome basses richesses (SBR), characterized by yellowing, deformed leaves and low beet yields. Having observed potato fields in Germany infested with cixiid planthoppers and showing signs of leaf yellowing, we used morphological criteria and COI and COII as molecular markers, to identify the planthoppers (adults and nymphs) primarily as P. leporinus. We analyzed planthoppers, potato tubers, and sugar beet roots and detected both pathogens in all sample types, confirming that P. leporinus adults and nymphs can transmit the bacteria. This is the first time that P. leporinus has been shown to transmit Arsenophonus to potato plants. We also found that two generations of P. leporinus were produced in the warm summer of 2022, which will probably increase the pest population size (and thus the prevalence of SBR) in 2023. We conclude that P. leporinus has expanded its host range to potato, and can now utilize both host plants during its developmental cycle, a finding that will facilitate the development of more efficient control strategies.