Insecticidal Activity of the Leaf Essential Oil of Peperomia borbonensis Miq. (Piperaceae) and Its Major Components against the Melon Fly Bactrocera cucurbitae (Diptera: Tephritidae).

The essential oil from the leaves of Peperomia borbonensis from Réunion Island was obtained by hydrodistillation and characterized using GC-FID, GC/MS and NMR. The main components were myristicin (39.5%) and elemicin (26.6%). The essential oil (EO) of Peperomia borbonensis and its major compounds (myristicin and elemicin), pure or in a mixture, were evaluated for their insecticidal activity against Bactrocera cucurbitae (Diptera: Tephritidae) using a filter paper impregnated bioassay. The concentrations necessary to kill 50% (LC ) and 90% (LC ) of the flies in three hours were determined. The LC value was 0.23 ± 0.009 mg/cm and the LC value was 0.34 ± 0.015 mg/cm for the EO. The median lethal time (LT ) was determined to compare the toxicity of EO and the major constituents. The EO was the most potent insecticide (LT  = 98 ± 2 min), followed by the mixture of myristicin and elemicin (1.4:1) (LT  = 127 ± 2 min) indicating that the efficiency of the EO is potentiated by minor compounds and emphasizing one of the major assets of EOs against pure molecules.