Integrated Pest Management in Action – Derogation for Use of the Neonicotinoid, Thiamethoxam in Sugar Beet in 2022

Abstract

In his days as an employed person the author, working as an entomologist at Broom's Barn Sugar Beet Research Centre (1984–2006), his job was to assess the efficacy of the various neonicotinoid seed treatments that were coming through development from various companies. Subsequently the best of these, imidacloprid initially, followed a few years later by clothianidin and thiamethoxam, were registered for use in sugar beet, and they revolutionised pest control in that crop in the UK and across Europe. They displaced older chemicals such as the carbamate granules aldicarb, benfuracarb, carbofuran and furathiocarb; they displaced even older sprays such as the organochlorine, gamma HCH. They reduced the need for sprays to control aphids and other early season foliar pests such as leaf miners (Pegomya betae). Neonicotinoids effectively did him out of a job in the end, and his team was disbanded in 2006. However, he is not bitter. They helped the sugar beet industry take control of the myriad of pests that affected this vulnerable crop, and I felt it was a job well done. During the time that we were assessing these novel treatments, He tried very hard to persuade the sugar beet industry to consider an IPM approach to their use, partly because he was worried that the widespread use of the active ingredients as insurance treatments might result in selection for resistance in the targeted pests, especially the aphids. He even produced a model to support the approach, which would have allowed forecasts to be made as early as mid-February. Unfortunately, the powers that be at the time did not agree with him, and proceeded to introduce the seed treatments without consideration of need. Back then, the seed treatment process required the seed to be treated in December, or January at the latest, before any accurate forecast could be made, especially for control of aphids. The sugar beet crop back then was also grown on over 200,000 ha, double the hectarage of today. The decrease in area grown in the UK was due to changes in the EU sugar regime, that resulted in reduced prices, and greater competition from other crops, which gave and still give higher returns. How times change. Here we are 20 years later with better seed treatment technology in place that allows precisely what we were trying to do back in the 1990s, namely to make treated seed available only if the forecast for national virus yellows infection is above an acceptable threshold for use. He thinks it is ironical that it took an epidemic of virus yellows in 2020 to persuade the sugar beet industry that this could and should be done, and that neonicotinoids could be employed using IPM principles. Thankfully the government has agreed that this is an acceptable practice with a banned chemical when effective alternatives are not available.