INSECTICIDAL ACTIVITY OF THE ESSENTIAL OIL ISOLATED FROM Azilia eryngioides (PAU) HEDGE ET LAMOND AGAINST TWO BEETLE PESTS

A large number of plant essential oils have been used against diverse insect pests since they, unlike conventional pesticides, present no risk to humans and the environment. This study was conducted to determine the toxicity of Azilia eryngioides (Pau) Hedge et Lamond (Apiaceae) essential oil against 1to 7-d-old Sitophilus granarius (L.) (Curculionidae) and Tribolium castaneum (Herbst) (Tenebrionidae) adults. The essential oil was obtained from aerial parts of the plant using a Clevenger apparatus and analyzed by gas chromatography and mass spectrometry. The major constituents of the oil were α-Pinene and bornyl acetate. Fumigation bioassays revealed that A. eryngioides oil had a strong insecticidal activity on adult test insects that were exposed to 37.03, 74.07, 111.11, and 148.14 μL L-1 to estimate mean lethal time (LT50) values. Mortality increased as concentration and exposure time increased, and reached 100% at the 39-h exposure time and concentrations higher than 111.11 μL L-1. Another experiment was designed to determine the mean lethal concentration at the 24-h exposure time (LC50)-, and these values indicated that S. granarius was more susceptible than T. castaneum. It can be concluded that the essential oil of A. eryngioides has potential against two stored-product pests, S. granarius and T. castaneum.