Efficacy of neonicotinoid and non-neonicotinoid treatments on virus yellows and sugar beet yields

Abstract

Myzus persicae (Sulzer), commonly known as the green peach aphid, plays a pivotal role in transmitting a range of yellowing viruses, including beet yellows virus, beet mild yellowing virus, beet chlorosis virus, and beet mosaic virus, to sugar beet plants (Beta vulgaris L.). Because of their environmental impacts, three neonicotinoid-based products (imidacloprid, thiamethoxam thiamethoxam, and clothianidine) have faced recent bans in multiple countries and there is thus an increasing need to explore alternative and effective methods for aphid control.In this study, we assess the efficacy of seven conventional aphicides, one neonicotinoid seed treatment, two foliar-applied neonicotinoids, and four companion plants in mitigating the propagation of virus yellows and increasing sugar beet yields. Our analysis is based on data obtained from 64 trials conducted from 2018 to 2022 2023 in France, Belgium, and the Netherlands. These trials were analyzed using linear mixed-effect models in order to estimate the efficacy of neonicotinoid and non-neonicotinoid treatments on the virus yellows and the sugar-beet yields.Our results revealed that the neonicotinoid seed treatment thiamethoxam exhibited strong efficacy in both reducing virus yellows and enhancing yields compared to alternative treatments. However, the most effective treatment for reducing virus yellows was a composite treatment combining barley companion plant, spirotetramat, and flonicamid, which led to an 87.0% reduction in virus yellows incidence compared to the untreated control group [95% confidence interval = (73.3; 93.6)]. In terms of sugar beet yields, spirotetramat at a dosage of 0.75 l/ha proved to be the most effective treatment, resulting in a 15.7% increase in yields compared to the untreated group [95% confidence interval = (9.1; 22.6)]. While companion plants were able to reduce virus yellows, they did not significantly increase yields compared to the untreated treatment. This outcome may be attributed to the competitive interactions between companion plants and sugar beets, in the context of dry seasons. Furthermore, our analysis indicated that the impact of spirotetramat, sulfoxaflor, flonicamid and thiamethoxam on yields tended to increase with higher aphid pressures.