Evaluation of Pimpinella anisum essential oils on egg-laying behaviour of Drosophila suzukii: A Multiple-choice test approach

Drosophila suzukii, spotted wing drosophila, is recognized as an economically significant new invasive pest of stone and, especially, berry fruits. This pest has been registered on the EPPO-A2 quarantine list. Due to the limited presence of natural predators on the European continent, this pest quickly proliferates, posing a significant threat to the agricultural economy by causing substantial losses in fruit production. As D. suzukii infestations commonly occur during the ripening stage, the main obstacle with chemical control methods is the risk of high residue in fruits. To face this issue, it is crucial to explore alternative control strategies. One of the possible effective methods involves the use of plant-derived bioactive compounds. Currently, there is ongoing research to identify essential oils with potential insecticidal properties for combating this challenge. The objective of this study was to assess the insecticidal and behavioural impacts of anise (Pimpinella anisum L.) essential oils on D. suzukii adults in a multiple-choice test using blueberries treated with three concentrations of the anise essential oil. Additionally, the study monitored the emergence of adults from the treated berries. Using GC-MC chromatography, the chemical composition of anise essential oil was determined, in order to understand the possible mode of action. The essential oil of anise showed high efficacy in the multiple choice test, since a lower number of laid eggs was recorded at all three application concentrations (1%, 5% and 10%) compared to the control (water and acetone). Our findings suggest that anise essential oil can serve as an alternative to chemical insecticides, which would enable the use of bioinsecticides based on this oil, in conventional, integrated, and organic crop production.