Chemical composition and biopesticide efficacy of the essential oil obtained by co-distillation of Cymbopogon citratus and Mentha piperita from Western Burkina Faso

Essential oils (EO) of Mentha piperita L. and Cymbopogon citratus (DC.) Stapf is a potential source of molecules with bioparasiticidal activity. The development of optimized combinations of these natural substances would allow them to be used as biopesticides. Thus, the objective of this study is to determine the biopesticide efficacy of EO obtained by co-distillation of these two plants from western Burkina Faso. GC/MS analyses show that the EO obtained by co-distillation of the dry leaves of C. citratus and M. piperita (CC/MP: 80/20) contains mainly citral (49.26%), β-myrcene (10.98%), menthol (5.90%) and menthone (4.50%). The EO of C. citratus contains mainly citral (74.32%) and β-myrcene (13.66%) while that of M. piperita contains mainly menthol (37.4%), menthyl acetate (17.4%), menthone (12.7%), limonene (6.9%), menthofuran (6.8%) and 1,8-cineole (5.6%). All major constituents of the two pure EOs were identified in the component of their mixture (CC/MP*: 80/20), but at lower levels. All EOs inhibited 100% of the mycelial growth of Macrophomina phaseolina and Phoma sorghina at doses of 0.6 and 0.2%. At the lowest dose tested (0.05%), inhibition rates were 49.63; 39.52 ; 39.52% and 26.33% on M. phaseolina; 41.13 ; 40.90 ; 19.67% and 21.50% on P. sorghina for EO/CC/MP, C. citratus, M. piperita and CC/MP*, respectively. All EOs, with the exception of M. piperita, resulted in 100% mortality of the susceptible strain of Anopheles gambiae at a dose of 1%. However, at the same dose, on the resistant strain, the mortality rates were 21.11; 2.47 ; 8.56% and 3.33% for EO, CC/MP, C. citratus, M. piperita and CC/MP*, respectively. This study shows that the co-distillation of C. citratus and M. piperita improves the biopesticide efficacy of their EOs.Keywords: C. citratus; M. piperita; co-distillation; essential oil; Efficacy of biopesticides