Incidence and environmental drivers of beet mild yellowing virus, beet chlorosis virus and beet yellows virus in sugar beet fields in Flanders

Since the ban on neonicotinoids, aphid-transmitted yellowing viruses have increasingly reduced sugar beet yields, leading to substantial economic losses. With limited sustainable alternatives, understanding virus incidence and its drivers is essential for effective disease prevention. This study examined the prevalence and incidence of major yellowing viruses in sugar beet crops across Flanders and assessed the influence of aphid abundance and environmental factors to identify key drivers of infection. We evaluated the incidence of beet
mild yellowing virus (BMYV), beet chlorosis virus (BChV), and beet yellows virus (BYV) in 25 sugar beet fields and investigated the influence of aphid abundance, soil nutrients, weather conditions, and landscape features on virus incidence. BMYV was the most prevalent virus detected. Higher incidences of BMYV and BYV were associated with earlier sowing dates and increased early-season abundance of Myzus persicae. BMYV incidence increased under warmer, wetter conditions, while BYV showed the opposite trend. Incidences of BChV and BYV increased
in areas dominated by sugar beet cultivation. Elevated soil concentrations of phosphorus and potassium were only associated with higher BMYV incidence. The incidence of yellowing viruses in Flanders was primarily driven by early-season aphid pressure and environmental conditions that facilitate virus transmission and establishment. The increasing occurrence of yellowing viruses poses a significant threat to sugar beet production and calls for better insights into the
factors driving virus infection and spread. Effective preventive management strategies should integrate pest dynamics, weather forecasting, landscape structure, and soil health intoinformed decision-making to limit further spread of yellowing viruses.