The toxicity of melissa and savory essential oil constituents against adult Bemisia tabaci was examined using vapor-phase toxicity bioassay. Results were compared with those following the treatment with currently used insecticide dichlorvos. As judged by 24 h LC50 values, thymol (0.59×10-3 mg/cm3) was the most toxic constituent, followed by cavacrol (0.60×10-3 mg/cm3). These compounds were slightly less toxic than dichlorvos (LC50, 0.20×10-3 mg/cm3). Strong activity was also obtained from borneol (LC50, 1.06×10-3 mg/cm3), α-terpineol (1.22×10-3 mg/cm3), geraniol (1.23×10-3 mg/cm3), linalool (1.33×10-3 mg/cm3), lavendulol (1.44×10-3 mg/cm3), nerol (1.52×10-3 mg/cm3), β-citronellol (1.81×10-3 mg/cm3), terpinene-4-ol (1.87×10-3 mg/cm3), 1-octen-3-ol (2.06×10-3 mg/cm3), and citral (2.34×10-3 mg/cm3). The melissa and savory essential oil-derived compounds, particularly thymol and carvacrol, merit further study as potential insecticides for the control of B. tabaci.

• Song-Hwa Chae(Department of Agricultural Biotechnology, Seoul National University)
• Jun-Ran Kim(Department of Agricultural Biotechnology, Seoul National University)
• Sang-Gyeu Lee(Rural Development Administration)
• Soon-Il Kim(NaturoBioTech Research institute)
• Young-Joon Ahn(WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University)