The impact of host fruit on parasitism of spotted wing drosophila (Drosophila suzukii) by Ganaspis kimorum

Drosophila suzukii (Diptera: Drosophilidae) is a global invasive pest of soft-skinned fruits, causing major economic losses in several important crops. Biological control of D. suzukii via releases of Ganaspis kimorum (Hymenoptera: Figitidae), a specialist larval endoparasitoid, has recently been more thoroughly studied as a promising addition to an integrated pest management strategy. This study examined whether parasitism success by G. kimorum varies with host fruit type, focusing on raspberries, blackberries, and blueberries, economically important crops used by D. suzukii. Ripe fruit was infested by a laboratory colony of D suzukii and then exposed to G. kimorum, and emergence of parasitoids and surviving flies was recorded. Significantly higher parasitism rates and reduced D. suzukii emergence were recorded in blueberries, while parasitism in raspberries and blackberries was less effective and not statistically different from controls unexposed to G. kimorum. These differences may be linked to fruit traits such as skin thickness, firmness, or internal structure, which can influence larval accessibility and parasitoid oviposition success. This highlights the importance of the host fruit environment in the efficacy of introduced parasitoids. This research allows for better targeting for biological control efforts by identifying fruit types where G. kimorum is most likely to contribute to D. suzukii suppression in the field.