Biological Control of Drosophila suzukii in South Tyrol (Italy) using the Exotic Parasitoid Ganaspis kimorum

Abstract

The spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), is a highly invasive fruit pest that has rapidly spread across Europe, the Americas, and parts of Africa since 2008. Its ability to oviposit in intact ripening fruits makes it particularly destructive, with infestations leading to severe economic losses in stone fruits, berries, and grapes. In Italy, the Ministry of the Ecological Transition (MiTE) authorized the release of the exotic larval parasitoid Ganaspis kimorum (Hymenoptera: Figitidae) in 2021 under a National Biological Control Plan. The initiative included releases in several regions and in the Autonomous Province of Bolzano/Bozen, where fruit orchards and surrounding habitats were selected as release sites based on confirmed D. suzukii infestations and minimal pesticide use. This study presents monitoring results from South Tyrol between 2021 and 2024, focusing on the establishment, spread, and overwintering of G. kimorum as well as the presence and abundance of other parasitoid species that emerged from the sampled fruits.