Decision making in controlling virus yellows of sugar beet in the UK.

Virus yellows is an important disease affecting yield in sugar beet in the UK. Myzus persicae (Sulzer) is the most effective and efficient aphid vector of the three viruses causing the disease: beet yellows virus, beet mild yellowing virus and beet chlorosis virus. Control of virus yellows disease is thus focused on the study and control of this aphid species. UK national surveys of virus yellows began in 1946 and these data helped to formulate disease forecasting schemes to optimise control. Over the years, in addition to improvements in farm hygiene, periodic changes and developments in control of the disease have occurred. To accommodate these important developments, virus yellows forecasting schemes have evolved accordingly. The most recent version has been adapted to take account of the current widespread use of imidacloprid seed treatment. Its application offers potential to optimise the rational use of aphicides such as imidacloprid so as to benefit beet growers and the environment by reducing prophylactic use of seed treatment.