Evaluating Drosophila suzukii oviposition behavior and Ganaspis kimorum oviposition and parasitism across four blueberry cultivars

Drosophila suzukii, commonly known as the spotted-wing drosophila, is a highly invasive pest of small fruits, including blueberries, capable of causing significant economic losses through its unique ability to oviposit in ripened fruit. The introduction of Ganaspis kimorum, a larval endoparasitoid, presents a promising biological control agent; however, the success of parasitism may vary depending on fruit characteristics and host resistance. This study evaluated the oviposition behavior of D. suzukii and the parasitism performance of G. kimorum across four blueberry cultivars: southern highbush (farthing), rabbiteye (savory), deerberry (V. stamineum), and F1 hybrid (V. corymbosum × V. stamineum). A series of no-choice and choice tests was conducted to assess cultivar-specific differences in SWD oviposition rates and preference. Fruit firmness was quantified using a penetrometer and correlated with both fly oviposition and parasitoid performance. Additionally, a four-arm olfactometer assay was used to evaluate D. suzukii behavioral responses to volatiles emitted by the cultivars. Parasitism trials measured G. kimorum’s offspring emergence and parasitism success in relation to cultivar firmness and infestation levels. This research deepens our understanding of how host plant traits influence pest-parasitoid interactions and support the development of integrated pest management strategies that leverage cultivar selection to enhance biological control efficacy.