Chemical composition and bioactivity of Piper auritum and P-multiplinervium essential oils against the red flour beetle, Tribolium castaneum (Herbst)

Stored grain insects have shown resistance to synthetic insecticides, fact that has promoted the use of vegetable species for integrated pest management. Piper auritum and P. multiplinervium are two plants from the Piperaceae family present in the department of Choco, Colombia, one of the most important hot spots of biodiversity in the world. This study was conducted to determine the repellent activity and toxicity of essential oils (EOs) isolated from these plants against Tribolium castaneum, using the area preference and contact toxicity methods, respectively. P. auritum EO presented greater repellency than P. multiplinervium, the first showed 100% lethality at minimum tested exposure period (24 h) whereas the second reached 16% at 72 h. EOs were analyzed by gas chromatography-mass spectrometry. P. auritum major components were safrole (93.2%) and miristicine (4.3%), whereas for P. multiplinervium were beta-elemene (9.0%), trans-beta-caryophyllene (5.3%) and caryophyllene oxide (4.1%). It is speculated that the repellent effect of P. auritum may be related to its safrole content, a known repellent. These results evidenced Piper species could be used for development of repellents against T. castaneum.