The effects of Beet mild yellowing virus and Beet chlorosis virus on the yield of UK field‐grown sugar beet in 1997,1999 and 2000

Abstract

SummaryThe separate effects of the aphid‐transmitted poleroviruses; Beet mild yellowing virus (BMYV) and Beet chlorosis virus (BChV), on the yield of field‐grown sugar beet were studied following different inoculation dates from May to July in 1997,1999 and 2000. Each sugar beet plant within the appropriate plots was infected with virus using at least 10 wingless viruliferous Myzus persicae per plant. In all 3 years, overall yield losses caused by BMYV were negatively correlated with time of infection with early season (May) inoculations causing 18–27% losses in sugar yield but late season losses only 4–15%. BChV decreased the sugar yield and sugar content of beet following early season inoculations, although the effects on sugar yield were more variable (range 8–24%) and the virus appeared to be less damaging compared to BMYV. However, inoculations with BChV in July of each year caused greater root and sugar losses than inoculations with BMYV at that time. Both poleroviruses increased the sodium content of the roots early in the season, although neither virus had an effect on potassium levels at any stage.