Spread of bacterial and virus yellowing diseases of sugar beet in South and Central Germany from 2017–2020

From 2017 to 2020 an extensive monitoring for bacterial and viral yellowing diseases was carried out in southern and central Germany. The monitoring recorded for the first time the infestation of sugar beets with yellowing viruses and the disease „Syndrome Basses Richesses“ (SBR). To map the yellowing virus infestation, samples were examined for the presence of several virus species (BYV, BtMV, poleroviruses). The disease SBR was investigated in this study using the more common g-3 proteobacterium “Candidatus Arsenophonus phytopathogenicus”. In this study samples were chosen, which showed yellowing symptoms. The coordination of the sampling was carried out by the Association of Hessian-Palatinate Sugar Beet Growers. Results clearly show the extent of the heavily infested area from SBR to southern Hesse, Rhine-Hesse and Franconia. The spread of SBR can be explained by the migration of the leafhopper Pentastiridius leporinus. Furthermore, the regional and parallel spread of mixed infections of both yellowing diseases was shown for the first time, which probably contributed to the strong sugar yield losses observed in practice. Causes and effects of mixed infections of both yellowing diseases require further research. Over the four-year study period, a continuous increase in SBR infections was observed. Therefore, the need for development of appropriate management systems to control SBR is very high.