Insect Vectors (Hemiptera: Cixiidae) and Pathogens Associated with the Disease Syndrome “Basses Richesses” of Sugar Beet in France

ABSTRACT The syndrome “basses richesses” (SBR) is a disease of sugar beet in eastern France associated with two phloem-restricted, nonculturable plant pathogens: a stolbur phytoplasma and a γ-3 proteobacterium, here called SBR bacterium. Three planthopper (Hemiptera: Cixiidae) species were found to live near and within sugar beet fields in eastern France: Cixius wagneri, Hyalesthes obsoletus, and Pentastiridius leporinus. The role of these planthoppers in spreading the two pathogens to sugar beet was studied. Based on its abundance and high frequency of infection with the SBR bacterium, P. leporinus was considered to be the economic vector of SBR disease. C. wagneri, the primary vector of ‘Candidatus Phlomobacter fragariae’ to strawberry in western France, also was found to be infected by the SBR bacterium and to transmit the pathogen to sugar beet. Neither C. wagneri nor P. leporinus were infected by stolbur phytoplasma. Populations of H. obsoletus living on bindweed (Convolvulus arvensis) and nettle (Ur...