National Research Council of Italy Portici, Campania, Italy
Among the natural antagonists of the invasive Drosophila suzukii (Spotted-Wing Drosophila=SWD) collected and characterized from the native area of the pest, the strain G1 of the larval parasitoid Ganaspis brasiliensis proved to be the most specific. For this reason, classical biological control programs based on the introduction of this species started in different countries including USA and Italy. Despite its current use, several aspects relative to the foraging behaviour of G. brasiliensis remain unexplored. In particular, it is not known whether the parasitoid orientates towards SWD-infested fruits, whether there is a time-related efficiency in the orientation towards SWD-infested fruits, whether there is a “preferred” host-fruit combination and which are the Volatile Organic Compounds (VOCs) released by host-infested fruits. To fill these gaps of knowledge olfactometer bioassays have been run in 3 different laboratories to test parasitoid preference towards different fruits and fruit-SWD combinations. Behavioural tests have been followed by the collection and characterization of VOCs released by uninfested and SWD-infested fruits. The results highlighted interesting differences that could have an important impact on the future use of G. brasiliensis in biological control programs against SWD.
