Biological control of the invasive pest Drosophila suzukii (SWD)

Spotted wing drosophila (SWD or Drosophila suzukii ), is a serious pest of commercial soft fruits and berries, infesting fruit early during the ripening stage, in contrast with other Drosophila species that infest only rotting fruit. Female SWD lay eggs inside sound fruit before harvest with her saw-like ovipositor, which contaminates fruit with larvae, and causes it to become soft and unmarketable.  Presently costly weekly applications of approved insecticides, both conventional and organic sprays, are effective at controlling SWD but need to be rotated with different insecticide chemical groups to avoid potential insecticide resistance issues with SWD. These sprays also disrupt beneficial insects and may lead to insecticide resistance in other insect pests. SWD can survive winter conditions by feeding on off native fruiting shrubs, but its impact on wild hosts are not well understood. Two species of Asian parasitoid wasps show promise as biological control agents, but must be demonstrated to be safe for introduction into Canada. Our Biocontrol team is working to assess the native and naturalized drosophila species to undergo quarantine host-specificity testing. Such testing is a key requirement to ensure endemic insects tested are not susceptible to attack. Canadian host range testing data will be combined with complementary work conducted by the USDA, to be submitted for a petition to release parasitoids into Canada. If successful, the release of biological control agents would reduce the economic and ecological impacts of both SWD itself, and impacts of its current control methods.