RESUMEN
Drosophila suzukii, an invasive insect pest, poses a significant threat to various fruit crops. The use of broad-spectrum insecticides to control this pest can reduce the effectiveness of biological control agents, such as the parasitoid Trichopria anastrephae. Here, we evaluated the toxicity of newly synthesized lactone derivatives on D. suzukii and their selectivity towards T. anastrephae. We used in silico approaches to identify potential targets from the most promising molecules in the D. suzukii nervous system and to understand potential differences in susceptibilities between D. suzukii and its parasitoid. Of the nine molecules tested, (rac)-8 and compound 4 demonstrated efficacy against the fly. Exposure to the estimated LC90 of (rac)-8 and compound 4 resulted in a mortality rate of less than 20% for T. anastrephae without impairing the parasitoid's functional parasitism. The in silico predictions suggest that (rac)-8 and compound 4 target gamma amino butyric acid (GABA) receptors and transient receptor potential (TRP) channels of D. suzukii. However, only the reduced interaction with TRP channels in T. anastrephae demonstrated a potential reason for the selectivity of these compounds on the parasitoid. Our findings suggest the potential for integrating (rac)-8 and compound 4 into D. suzukii management practices.
RESUMEN
The spotted wing drosophila (Drosophila suzukii) is one of the main invasive pests of small fruits in the world. Thus, 19 essential oils (EOs) were selected to analyze the effects through toxicity and repellency on oviposition and D. suzukii adults. In addition, their lethal and sublethal effects on the pupal endoparasitoid Trichopria anastrephae were evaluated. The EOs of C. flexuosus and Mentha spp. had the highest toxicity observed in the topical application bioassay for D. suzukii. In contrast, the EOs of C. verum, C. citratus QT citratus, and C. winterianus showed the highest toxicity in the ingestion bioassay for D. suzukii. The dry residues of C. verum and C. citratus QT citratus reduced the oviposition of D. suzukii. In the repellency bioassays, the 19 EOs analyzed repelled â 90% of the D. suzukii females. All EOs evaluated using the LC90 values of the products provided mortality of less than 20% of T. anastrephae adults and did not cause a reduction in the parasitism of surviving T. anastrephae females. We conclude that the EOs evaluated have the potential to be used in the management of D. suzukii. They can also serve as selective active ingredients for the formulation and synthesis of new biopesticides.
Asunto(s)
Himenópteros , Insecticidas , Aceites Volátiles , Animales , Agentes de Control Biológico , Drosophila , Femenino , Frutas , Control de Insectos , Insecticidas/farmacología , Aceites Volátiles/farmacologíaRESUMEN
Essential oils (EOs) produced by plants in the Lamiaceae family may provide new insecticidal molecules. Novel control compounds are needed to control Drosophila suzukii (Matsumura), a severe economic invasive pest of thin-skinned fruit crops. Thus, we characterized the main compounds of EOs from three rosemary Rosmarinus officinalis ecotypes (ECOs) and evaluated their toxicity to D. suzukii adults, deterrence of oviposition behavior, and histological alterations in larvae. Additionally, we analyzed the lethal and sublethal effect on the pupal parasitoid Trichopria anastrephae. The main compounds identified in the R. officinalis ECOs were α-pinene, camphor and 1,8-cineole. In bioassays via topical application or ingestion, ECOs and their major compounds showed high toxicity on D. suzukii adults and a lower concentration could kill 50% and 90% of flies compared to spinetoram. The dry residues of a-pinene, 1,8-cineole, and camphor provided a repellent effect by reducing D. suzukii oviposition by ~47% compared to untreated fruit. Histological sections of 3rd instar larval D. suzukii posttreatment revealed damage to the fat body, Malpighian tubules, brain, salivary gland, and midgut, which contributed to high larval and pupal mortality. Survival and parasitism by adult T. anastrephae were not affected. Thus, R. officinalis EO and their compounds have potential for developing novel insecticides to manage D. suzukii.