The Virus Yellows Epidemic in Sugar Beet in the UK in 2020 and the Adverse Effect of the EU Ban on Neonicotinoids on Sugar Beet Production

Abstract

Virus yellows, the disease that was regarded as the worst scourge of sugar beet production in northern Europe in the 20th century, made a dramatic and devastating comeback in 2020, infecting up to 100% of some fields in the Fens of Cambridgeshire, and culminating in 38.1% infection of the national crop, the highest incidence of this pernicious disease since the epidemics of 1974–1976. The causes of the latest epidemic were the consequences of a perfect storm – high overwintering survival of the principal vector, the peach potato aphid, Myzus persicae, following a very mild winter, that resulted in early migration of infective aphids from overwintering hosts into newly emerging beet crops in April. These events, coupled with removal by EU dictate of the most efficient method of controlling the disease, namely the neonicotinoid seed treatments that had kept it under control for the previous 26 years, and the depletion of alternative insecticide spray products, either due to other bans, or having been rendered ineffective by the development of resistance in the vectors, meant that growers were fighting a losing battle almost from the day they sowed their seed. This article examines in detail how the 2020 epidemic developed, and the impact it had on the profitability of the sugar beet industry in the UK, and other parts of Europe. We also argue for a return of neonicotinoid seed treatments in future years to provide more effective control of future pandemics, and thus maintain the presence of this important break crop in arable rotations.