Insecticide effect of pennyroyal and rosemary essential oils on the rice weevil

The study aims at evaluating the potential insecticide essential oils from two plants of the family Lamiaceae pushing the spontaneous state in the Tiaret region (western Algeria). Insecticides tests were performed in the laboratory by the direct contact method. The results of these tests have shown that rosemary essential oil has remarkable insecticidal properties. They induced 100% mortality of adult rice weevils to 15 mu l dose after only 24 hours of exposition. The essential oil of pennyroyal induced 70 % mortality at the same dose and for the same exposure time. Lethal doses (LD50) are determined in the order of 5,58 for rosemary and 7,36 mu l for pennyroyal. The LD90 Are in order of 9.36 mu l it mean between the second and third dose tested for the rosemary and of 12.52 mu l for the pennyroyal and in the same two essential oils experimental conditions prevent the development of rice weevil larvae Sitophylus oryzae to 5 mu l dose.