Comparaison de la composition chimique et I'activite insecticide des huiles essentielles de Mentha suaveolens Ehrh. prelevees de deux regions differences du Maroc contre Bruchus rufimanus (Bohman) (Coleoptera: Chrysomelidae)/Comparison of the chemical composition and the insecticidal activity of essential oils of Mentha suaveolens Ehrh. collected from two different regions of Morocco, against Bruchus rufimanus (Bohman) (Coleoptera: Chrysomelidae)

Morocco provides a large botanical treasure which can be the source of many interesting products for the development of new insecticides. The purpose of this study was to validate the therapeutic properties of Mentha suaveolens Ehrh. used heavily in Moroccan traditional medicine, to determine the chemical composition of its essential oils (EO) and to assess its insecticidal activity against Bruchus rufimanus .The leaves and flowers of M. suaveolens Ehrh. were collected in two regions of Morocco (Middle Atlas and Loukkos). The chemical composition of EO was analyzed by gas chromatography coupled to mass spectrometry. 41 The Constituents representative (99.12%) from that of Loukkos whereas 35 constituents representative (99.60%) of the Middle Atlas, the majority compound of the two oils is the oxide of piperitenone. The probabilities of survival and the values of the LC50 and LC99 reveal that the EO of M. suaveolens Ehrh. presents a strong insecticidal activity. This toxicity increases with the increase of the concentration and the duration of exposure. After 24h of exposure the EO of Loukkos proves to be more active than that of Middle Atlas. Therefore the insecticidal activity is intimately linked to the chemical composition of the oils tested. It can be inferred that the yield and the chemical composition of EO that were studied vary in function of the region of the plant as well as these oils studied can be used as botanical insecticides against B. rufimanus.