7: The evaluation of Asian parasitoids for the classical biological control of Drosophila suzukii – A worldwide project

On-Demand

Presenting Author(s)

Pierre Girod

The University of British Columbia
Vancouver, British Columbia, Canada

Co-Author(s)

M. Lukas Seehausen

Centre for Agriculture and Bioscience International (CABI)
Delémont, Jura, Switzerland
AA

Alexandre Aebi

University Neuchâtel
Neuchâtel, Neuchatel, Switzerland
TT

Ted C.J. Turlings

University Neuchâtel
Neuchâtel, Neuchatel, Switzerland
NR

Nicolas Ris

INRAE
Paris, Ile-de-France, France
Tim Haye

Centre for Agriculture and Bioscience International (CABI)
Delémont, Jura, Switzerland
MK

Marc Kenis

Centre for Agriculture and Bioscience International (CABI)
Delémont, Jura, Switzerland

Drosophila suzukii is an Asian species that is invasive in Europe and the Americas. In the search for an effective pest management strategy, researchers from different continents are joining to develop classical biological control programs. Surveys in Asia showed that parasitism is a main mortality factor but can be highly variable. Laboratory-based host range tests with Asian parasitoids of three genera demonstrated the highest specificity in the genus Ganaspis, although regional differences in specificity became evident. DNA analysis of specimens from different Asian regions identified the parasitiod as Ganaspis brasiliensis (Hymenoptera: Figitidae); however, results indicated a species complex exists. Crossing experiments further revealed that there are at least two reproductively isolated cryptic species with different behaviors. While one species is readily drawn to and parasitizes several drosophila species regardless of their food source the other one is almost exclusively specific to larvae feeding in ripening fruits. Because only D. suzukii attacks ripening fruits in its area of invasion, this second species appears to be well suited as a classical biological control agent. Thus, twelve years after the first detection of D. suzukii outside its native range, researchers from around the world have identified a potential biological control agent and petitions for the release of the more specific Ganaspis cf. brasiliensis are underway. Although some questions such as its climatic suitability for all invaded areas remain to be answered, the results indicate that classical biological control can soon be added as a promising pest management strategy against D. suzukii.