Bioactivity of essential oils in the control of Sitophilus ssp.

Abstract

Brazil is the largest rice producer outside of Asia, and the large production of this grain in the Brazilian territory has aspects that affect its productivity. Among all the influencing aspects is the rice weevil, Sitophilus ssp. Considering the needs of the grain industry and the market that seeks products without toxic residues, the work evaluated the bioactivity of the essential oils of laurel (Laurus nobilis), eucalyptus (Eucalyptus citriodora), and mint (Mentha piperita) on the coleopteran Sitophilus ssp. The insects used were obtained from infested silos and kept in a breeding room at a controlled temperature. For testing the bioactivity of essential oils, essential oils were used at concentrations of 1%, 5%, and 10%. The adult insects used were placed on the plates and the count of live individuals (rice weevil) was performed at times of 15 min., 30 min., 60 min., 6h, 12h, and 24h. All tested oils showed efficiency in insect mortality. The chemical characterization of essential oils was performed by gas chromatography coupled with mass spectrometry, indicating the presence of oxygenated monoterpenes in the three essential oils analyzed.