Efficacy of Three Herbal Essential Oils Against Rice Weevil, <i>Sitophilus oryzae</i> (Coleoptera: Curculionidae)

Abstract

Sitophilus oryzae (L) were subjected to essential oils extracted from Mentha piperita L, Rosmarinus officinalis L and Hyssopus officinalis L. Chemical structure, repellency, fumigant toxicity and feeding reduction of the essential oils were investigated. Chemical composition of the essential oils of M. piperita, R. officinalis and H. officinalis were identified by GC-MS. Menthol (43.95%), menthone (8.28%) and 1,8-cineole (7.07%) were major components of M. piperita oil; α-pinene (23.52%), verbenone (11.87%) and 1,8-cineole (8.56%) were the main components of R. officinalis oil and cis-pinocamphone (23.39%), trans-pinocamphone (17.78%) and β-pinene (9.64%) were major components of H. officinalis oil. In fumigants bioassay, H. officinalis (78.16 μl/L) had the highest toxicity against S. oryzae adults, followed by R. officinalis (115.63 μl/L) and M. piperita (299.51 μl/L), respectively. Also, the S. oryzae was repelled by M. piperita (95.0%), R. officinalis (91.0%) and H. officinalis (86.5%), respectively. Based on measured nutritional indices of adults, the highest FDI and the lowest RGR, RCR, and ECI were obtained when adults were treated with M. piperita and H. officinalis at 10 μL/g food. In conclusion, H. officinalis essential oil was more potent for use in organic food protection.