Biological control of Drosophila suzukii using the larval parasitoid Ganaspis brasiliensis in Italy
Drosophila suzukii (Diptera: Tephritidae – EPPO A2) is a frugivorous fly native to East Asia. It has spread to many regions worldwide, including other parts of Asia, the Americas, Africa and the EPPO region. In 2021, after the evaluation of a comprehensive risk assessment submitted by Italian scientific institutions and phytosanitary services, the Italian Ministry of Ecological Transition authorised the release of Ganaspis brasiliensis G1 in seven regions and two autonomous provinces within the frame of a national biological control programme. G. brasiliensis was released in 12 locations in the Trento province. All sites were located at the margins of wooded areas thereby providing natural corridors for the parasitoid movement. At each site, a single release point was selected, and parasitoid releases (300 males and 300 females) were performed once a week for three consecutive weeks. At each site sampling was carried out, at least once pre-release and five times post-release. After the releases, G. brasiliensis was recovered at 50% of the locations. In at least two locations, G. brasiliensis was able to survive the cold season and to start new generations in spring. The parasitoid only emerged from D. suzukii, the latter being mostly collected from fresh fruit still on the plant.
Sources
Fellin L, Grassi A, Puppato S, Saddi A, Anfora G, Ioriatti C, Rossi-Stacconi MV (2023) First report on classical biological control releases of the larval parasitoid Ganaspis brasiliensis against Drosophila suzukii in northern Italy. BioControl, https://doi.org/10.1007/s10526-022-10174-2