Pimpinella anisum essential oil and trans-anethole activity against key insect pests and non-target ants

Pest control has faced several challenges during the last decades, increasing research about innovative ecofriendly bioinsecticides to replace and integrate the conventional strategies. In this scenario, botanical extracts are promising substances for pest management. In this study, we developed a novel small-scale sprayer for precision application of botanical insecticides on plant material; the insecticidal activity of the essential oil (EO) from cultivated aniseed, Pimpinella anisum L., and its main constituent trans-anethole (> 95% of the whole composition) was tested against three key polyphagous pests of fruit crops, as well as toward a non-target ant species, Crematogaster scutellaris (Olivier). Both the EO and its main constituent were effective against Lobesia botrana (Denis & Schiffermüller) larvae, as well as against Ceratitis capitata (Wiedemann) adults in ingestion toxicity trials. However, C. capitata (LC₅₀ 0.97 and 0.80 µL/mL for EO and trans-anethole, respectively) was more susceptible than L. botrana (LC₅₀ 38.71 and 24.16 µL/mL for EO and trans-anethole, respectively). Furthermore, both the EO and trans-anethole tested at 45 μL/mL had a high antifeedant effect (> 80%) on Spodoptera littoralis (Boisduval) larvae. From a non-target point of view, P. anisum EO caused moderate lethality on C. scutellaris ants, with significant reduction of survival after 96 h at the highest tested concentration. Overall, aniseed EO could represent a valuable bioinsecticide which could be used in the field at low concentration for organic management of polyphagous crop pests.