First occurrence of Dacus frontalis in Belgium: what’s next?

True fruit flies (Diptera: Tephritidae) comprise over 4,500 species across more than 500 genera and are found throughout the world. They thrive mainly in (sub)tropical regions and several species are recognised as major agricultural pests, causing billions of euro in damage annually. One of these tephritid species, the pumpkin fruit fly, Dacus frontalis, is a notable pest of cucurbits and is classified as a quarantine pest within the European Union. Previously, D. frontalis had only been reported in North, East, and South African countries, with no documented occurrences in Europe.

The Belgian NPPO, i.e. the Federal Agency for the Safety of the Food Chain (FASFC), detected D. frontalis for the first time on Belgian territory during an annual monitoring campaign for quarantine organisms imposed by the EU. A single male D. frontalis adult was detected on September 18, 2024, in a trap baited with ammonium bicarbonate/ammonium sulphate at a waste container near a wholesale market for fruit and vegetables at the Quai des usines in Brussels. Morphological analysis, corroborated by sequencing of a fragment of the cytochrome oxidase subunit I (COI) gene, confirmed that this fruit fly specimen was D. frontalis.

The most likely explanation for the presence of D. frontalis near a wholesale market in Belgium is that this fruit fly has travelled as an egg or larva with imported fruit. Future research should determine whether the occurrence of D. frontalis in Belgium is an isolated incident or indicative of potential establishment.