Chemical composition of essential oils of selected species of Piper and their insecticidal activity against Drosophila suzukii and Trichopria anastrephae

The present study aimed to analyze the chemical composition of five species of the genus Piper (P. aduncum L.; P. crassinervium Kunth.; P. malacophyllum Prels.; P. gaudichaudianum Kunth.; P. marginatum L.), and assess their toxicity to the adults of Drosophila suzukii (Diptera: Drosophilidae) and the pupal parasitoid Trichopria anastrephae Lima (Hymenoptera: Diapriidae). The major compounds were monoterpene hydrocarbons (5.3-60.9%); oxygenated monoterpenes (13.3%); sesquiterpenes hydrocarbons (8.3-45.3%), oxygenated sesquiterpenes (5.2-58.8%); and arylpropanoids (15.2-29.6%). In bioassays of ingestion and topical application, essential oils (EOs) from P. aduncum, P. gaudichaudianum, and P. marginatum killed approximately 100% of adults of D. suzukii, similarly to the insecticide based on spinetoram (75 mg L-1) (96.2% of mortality). Besides, the dry residues from P. aduncum, P. gaudichaudianum, and P. marginatum provided a repellent effect on oviposition ( approximately equal to 7 eggs/fruits) and negative effects on egg viability ( approximately equal to 2 larvae/fruits) of D. suzukii on artificial fruits. Based on the estimate of the lethal concentration required to kill 90% of exposed flies, EOs from P. aduncum, P. crassinervium, P. gaudichaudianum, P. malacophyllum, and P. marginatum provided low toxicity to the parasitoid T. anastrephae in a bioassay of ingestion and topical application (mortality < 20%), similarly to the water treatment ( approximately equal to 5% of mortality). EOs of Piper species tested in this work showed to be promising plant insecticides for the management of D. suzukii.