Economic viability of companion plants to lower the spread of virus yellows in sugar beets

Following EU’s decision to ban neonics, several alternative solutions have emerged from the dedicated French national research program initiated in 2020. Companion plants, such as barley or oats, sown at the same time as beets, proved to have a repellent effect and reduce aphids’ presence in sugar beet fields. This paper evaluates the economic viability of this particular solution and assesses how it reduces the risk of sugar beet infections by virus yellows. We show that although companion plants may be effective in repelling aphids, the strict economic impact associated with the reduction of aphids’ population is mainly negative under cost-benefit assumptions currently adopted. Our analysis is based on the incidence model developed by Qi et al. It factors in costs induced by the planting and destruction of companion plants at a [4–6] leaf stage and factors in a ”competition” effect between companion plants and beets. As a consequence of our analysis, we highlight the need to run further research work in two directions, (1) analyze the potential of additional benefits offered by the solution to complement its strict impact on the number of aphids in sugar beet fields and (2) analyze potential benefits offered by synergies and combinations of companion plants with other viable solutions used to mitigate the spread of virus yellows in sugar beets. • The companion plants repel aphids, which infect sugar beet plants. • This paper presents a cost-benefit economic analysis of the companion plants solution. • The use of companion plants is almost never a viable economic solution within the framework of our cost-benefit assumptions. • Simulate cultural strategies to respond to climate change and the transition to agro-ecological practices.