VIRTAB: Assessing the risk of whitefly-transmitted viruses for Belgian crops

Whiteflies such as Trialeurodes vaporariorum and Bemisia tabaci are devastating pests on crops like tomato or cucumber and cause annual yield losses of more than 1 billion euro worldwide. In addition to physically damaging plants, they are also well-known to transmit detrimental plant viruses, with more than a hundred documented plant viruses for B. tabaci. For the latter, a distinction is made between European and non-European populations (i.e. found in imported produce and ornamental plants from non-European countries), with non-European populations being considered as quarantine pests. However, the current status of B. tabaci populations in Belgium is not well-known, with only a restricted distribution reported in Belgium, whereas in the Netherlands they are widespread, according to the EPPO global database. In addition, whether the B. tabaci populations in Belgium or those B. tabaci specimens intercepted at customs (non-European populations) carry whitefly-transmitted viruses that could pose a risk to Belgian greenhouse crops, is currently unknown. In 2022, the Flanders Research Institute for Agriculture, Fisheries and Food (ILVO) and the Vegetable Research Centre (PCG) will jointly work on a project named VIRTAB (funded by the Belgian FPS Public Health) to fill this knowledge gap and use both classical molecular techniques as high-throughput sequencing to identify and characterize viruses that are present in non-European B. tabaci populations as well as those present in B. tabaci populations (and their host plants) in Belgium. The identification of whitefly-transmitted viruses will provide insight into the potential impact of B. tabaci and other whiteflies on Belgian greenhouse crops and the possible measures to be taken. In the light of the current climate change, with B. tabaci populations also spreading to more northern regions as well as occurring outdoors, this information needs to be gathered sooner rather than later.