Virus Screening in Bemisia tabaci : A Belgian Study on Emerging Plant Viral Risks

The silverleaf whitefly Bemisia tabaci is a notorious agricultural pest, causing over a billion euros in crop damage annually worldwide. Its primary impact comes from its ability to transmit plant viruses, including begomoviruses, criniviruses, and other emerging pathogens. In the European Union (EU), B. tabaci is considered as a quarantine pest when intercepted on non-EU plant imports. However, its local virological risks to greenhouse crops in Belgium remained underexplored. Between 2021 and 2024, over 50 B. tabaci populations were intercepted on imported plant material at key points of entry in Belgium, while additional populations were collected from EU and Belgian-grown crops and ornamentals. Comprehensive virus screening was conducted using classical molecular techniques and high-throughput sequencing to: 1) Characterize the viral communities associated with B. tabaci populations, 2) Identify the biotypes of intercepted and local whitefly populations, and 3) Screen for mutations linked to insecticide resistance. The screening revealed diverse range of viruses in B. tabaci, including criniviruses and begomoviruses. The majority of collected whiteflies belonged to two biotypes and resistance mutations were identified in both non-EU and local populations, complicating management strategies. This study underscores the critical role of virus-vector surveillance in mitigating emerging plant viral threats. By integrating virological and entomological approaches, we provide insights into the risks posed by B. tabaci-vectored viruses, supporting the development of targeted phytosanitary measures to protect greenhouse crops in Belgium.