Background: Although the pupal parasitoid Trichopria drosophilae is used in conservative and augmentative biocontrol of Drosophila suzukii infestations, current pest management strategies mostly rely on multiple insecticide applications. In this context, the aim of the study was to investigate the baseline toxicity of nine insecticides on D. suzukii larvae and their multiple sublethal effects (LC ₁₀ ) on immature stages of the pest feeding on contaminated diet and T. drosophilae developing within the intoxicated host . Results: Chlorpyriphos and azadirachtin showed the lowest and the highest LC ₁₀ , the values of which were 9.78 × 10 ¹³ and 1.46 × 10 ³ times lower than their recommended label field rate, respectively. Among tested insecticides, imidacloprid, malathion and dimethoate were the only treatments that did not affect the juvenile development time of D. suzukii , while spinosad and the organophosphates chlorpyriphos and dimethoate did not influence fly pupal size. No sublethal effects were recorded on T . drosophilae degree of infestation (DI) and juvenile development time. On the contrary, cyazypyr and dimethoate negatively affected the success of parasitism (SP) and the number of progeny of the pupal parasitoid, in association with malathion for the first parameter and spinosad for the fertility. Compared to the untreated control, more female progeny emerged following azadirachtin exposure, while dimethoate caused the opposite effect. Imidacloprid, lambda‐cyhalothrin and spinetoram decreased hind tibia length of emerged parasitoids. Conclusion: This study provides new insights on the (eco)toxicological profile of nine insecticides and new information needed to support the deployment of T. drosophilae in the field within the sustainable management techniques against D. suzukii . © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Drosophila suzukii and Tuta absoluta are successful biological invaders of agroecosystems. Their integrated pest management (IPM) programs involve the release and/or conservation of natural enemies. Among these, Ganaspis kimorum is a major Asian parasitoid of D. suzukii and has been introduced as a classical biological control agent of this pest in Europe and North America, while Necremnus tutae is a key fortuitous parasitoid of T. absoluta in the Mediterranean region. Bioinsecticides represent key alternatives to chemicals for controlling both pests. This study investigated the potential compatibility of both parasitoids with Beauveria bassiana, Bacillus thuringiensis, garlic essential oil (EO), and spinosad, in comparison to two synthetic insecticides, cyantraniliprole and chlorantraniliprole. The results showed that combining each of the tested insecticides with G. kimorum slightly increased pest mortality compared to the insecticide alone. Necremnus tutae had a significant additive effect on host mortality when combined with insecticides. Beauveria bassiana and B. thuringiensis were most compatible with both parasitoid species. Both garlic EO and chlorantraniliprole impaired the survival of immature N. tutae and showed sublethal toxicity on the reproductive and non-reproductive behaviors of N. tutae. Spinosad exhibited high acute toxicity on both juvenile and adult parasitoids of both species. Overall, these findings provide useful insights into insecticide selectivity toward two key parasitoids and offer new knowledge on the potential of combining natural enemies and bioinsecticides for optimized IPM.

Background: The spotted wing drosophila, Drosophila suzukii , is an invasive pest causing significant economic losses worldwide. Current pest control strategies mainly rely on insecticides, which negatively impact fruit marketability and the sustainability of integrated pest management (IPM) programs. In addition, pesticides can have dramatic consequences on non-target species when persisting in the environment at low concentrations after field applications. In this context, chemical control can strongly interfere with the releases of the G1 strain of the Asian larval parasitoid Ganaspis cf . brasiliensis , which is currently the adopted classical biological control agent to manage D. suzukii infestations worldwide. Methods: Probit analysis was used to assess the baseline toxicity of acetamiprid, cyazypyr, lambda-cyhalothrin, phosmet, and spinosad on G1 G. cf . brasiliensis adults through residual contact exposure in the laboratory. Then, adult parasitoids were exposed to insecticide low Lethal Concentrations (LC ₅ and LC ₃₀ ) and their mortality was checked daily to assess the survival of treated wasps. Results: Lambda-cyhalothrin showed the highest toxicity on the parasitoid with a LC ₅₀ of 1.38 × 10 ^–3 g active ingredient (a.i.) /L, while cyazypyr seemed the safer active ingredient with an estimated LC ₅₀ of 0.20 g a.i./L without affecting parasitoids at sublethal doses. Spinosad and phosmet significantly reduced wasp survival at both LC ₃₀ and LC ₅ , while lambda-cyhalothrin and acetamiprid affected parasitoid lifespan only at LC ₃₀ . Spinosad, lambda-cyhalothrin and phosmet LC ₃₀ caused the major survival reductions, followed by acetamiprid LC ₃₀ . The least significant reduction in parasitoid survival was 21.6% by spinosad LC ₅ . Conclusions: Overall, this study highlighted the importance of carefully selecting insecticides to minimize adverse effects on non-target organisms. In particular, cyazypyr was the most promising candidate to integrate inoculative biological control with chemical treatments. By contrast, the application of phosmet, spinosad and lambda-cyhalothrin should be avoided alongside parasitoid field releases. Although acetamiprid is less used against D. suzukii in the field than the other tested molecules, it should be used with caution due to its sublethal toxicity on the parasitoid. These results provide the first evidence of G . cf. brasiliensis susceptibility to insecticides in order to promote sustainable and efficient pest management strategies.

Spotted wing drosophila (SWD) causes significant economic loss in fruit crops to growers worldwide. There is immediate need for efficacious and selective monitoring tools that can detect infestations early. Previously, volatile organic compounds derived from apple were studied and a quinary chemical component blend (QB) was identified as the key SWD attractant in a blueberry orchard in the United States. This study's aim was to determine whether previously observed QB efficacy, selectivity, and early detection levels could be attained within raspberry and cherry fields in the USA and Europe. Results demonstrated that sticky trap baited QB dispenser provided earlier SWD detection potential than the usually adopted apple cider vinegar (ACV) trap. The number of SWD captured/trap by QB baited trapping systems was significantly lower than that of the ACV trap. However, percent SWD/trap of QB baited traps was same within cherry. Lower non-target capture will save farmer/grower's labor and time allocated to traps installation and drosophila species identification. Within the USA, SWD selectivity of QB baited liquid traps was consistently greater than sticky trap in raspberry field, suggesting that the QB dispenser can be an alternative to the standard ACV lure and that trap design could improve selectivity further.