Essential oils composition of four Myrtaceae of Tunisia origin and their biological activity against the cowpea weevil, Callosobruchus maculatus (F., 1775) (Coleoptera: Bruchidae) and Vigna unguiculata seeds

Abstract: Leguminous plants play a prime role in African populations food supply due to their high content in proteins and good preservation of the harvests is vital. Callosobruchus maculatus (Coleoptera: Bruchidae) is one of the most serious pests of leguminous seeds such as cowpea seed. In several African countries, during storage, many generations thrive and cause losses varying between 90 and 100%. Our work focuses on the identification of essential oils active elements of aromatic plants from Tunisia, and their biological activity against cowpea weevil. The results of gas chromatography coupled with mass spectrometry showed that monoterpene components predominate over sesquiterpene compounds. Their retention time is shorter compared to sesquiterpenes. The major component is the eucalyptol. The results of the biological activity of four essential oils on C. maculatus showed that the application at the dose of 25 μl /50 g of E. lehmani, E. astringens, E. maidenii and E. cinerea gave 100% mortality within 24 h, with no survival embryonic and post- embryonic. However, these treatments did not affect the seeds germination of V. unguiculata.