Occurrence and relative prevalence of sugar beet yellowing viruses in the UK between 2019-2022

Virus yellows disease (VY) is a global issue, caused by a complex of virus species and affecting sugar beet crops worldwide. Previous studies undertaken prior to the widespread use of neonicotinoid seed treatments had identified beet mild yellowing virus (BMYV) as the predominant cause of the disease in the UK. Up-to-date knowledge of the causal agent(s) of this disease is important for the successful deployment of integrated pest management strategies, including the use of resistant sugar beet varieties. However, only a limited number of studies have been conducted into the epidemiology of VY in recent decades. The findings of this three-year monitoring survey, utilising a novel small RNA sequencing approach, suggest beet chlorosis virus (BChV) as the most prevalent virus associated with VY in the UK during this period. In comparison to conventional detection tools, the methodology described here permitted the detection of non-target viruses including beet mosaic virus and beet cryptic virus, however no new causative agents of VY were identified.