First Experimental Release of Parasitic Asian Wasp to Control Spotted-Wing Drosophila

Ganaspis_brasiliensis_mirtillo (photo: Arnaud Conne, Agroscope) The invasive spotted-wing drosophila (SWD) is a devastating pest in berry, stone fruit and grape crops. A natural antagonist from the fruit fly-s area of origin in East Asia is now due to be released in Switzerland for the first time by Agroscope and CABI. The experimental releases in the Cantons of Jura and Ticino aim to clarify whether this parasitic wasp can become established in Switzerland to regulate the SWD population and reduce production losses. Originally from East Asia, the spotted-wing drosophila ( Drosophila suzukii ) has been recognised in North America and Europe as an invasive pest since 2008. In Switzerland, where it has no efficient natural enemies, its presence was first detected in 2011. As the only fruit fly species in Switzerland, their females lay eggs in undamaged ripening fruit, rendering it unfit for sale. In this way, Drosophila suzukii causes major economic damage in Swiss agriculture, particularly in berry, stone fruit and grape crops.