High-throughput sequencing surveillance of Bemisia tabaci: detecting plant viruses and insecticide resistance mutations

The whitefly Bemisia tabaci (Gennadius) is a major global crop pest, causing annual damages exceeding one billion euros. It is known to transmit over a hundred plant virus species, and is considered as a quarantine pest in the EU when found in non-European plant commodities. While reported to be present in Belgium, its distribution remains unknown, and it is unclear to what extent local and non-European populations pose phytosanitary risks to Belgian greenhouse cultures. Between 2021 and 2023, over 50 non-European B. tabaci populations were intercepted from imported commodities at ports of entry. Simultaneously, multiple B. tabaci populations were collected from local (European) crops and ornamental plants. Both classical molecular techniques and high-throughput sequencing were used to 1) identify the biotype of the whitefly, 2) characterise the viral load the whitefly carries and 3) screen for insecticide resistance mutations. The majority of the collected whiteflies belonged to two common biotypes, and several crini- and begomoviruses were detected. In addition, insecticide resistance mutations were identified in both European and non-European populations. Based on our screening survey, the potential threat posed by B. tabaci to Belgian greenhouse cultures will be assessed and a strategy will be developed to mitigate its impact on greenhouse cultivation in Belgium.