The toxicity of materials derived from rhizome of Cnidium officinale Makino to adults from B and Q biotype of Bemisia tabaci was examined using a leaf-dipping bioassay. Results were compared with those of two currently used insecticides: acetamiprid and thiamethoxam. The active principles of C. officinale rhizome were identified as butylidenephthalide (1), ligustilide (2), and 3-butylphthalide (3) by spectroscopic analysis. These compounds exhibited 100% mortality against both B and Q biotype adults at 2.5 mg/ml. At a concentration of 1.25 mg/ml, butylidenephthalide produced 88 and 92% mortality against B and Q biotype adults, respectively. 3-butylphthalide showed 100 and 89% mortality against B and Q type adults, respectively. Ligustilide exhibited 97 and 100% mortality against B and Q type adults, respectively. The toxicity of these compounds to B type adults was almost equal to that of thiamethoxam and acetamiprid, whereas two insecticides exhibited 40% mortality to Q biotype. C. officinale rhizome-derived materials merit further study as potential insecticides for the control of B. tabaci populations due to global efforts to reduce the level of highly toxic synthetic pesticides.

• Song-Hwa Chae(Entomology major, Department of Agricultural Biotechnology, Seoul National University)
• Soon-Il Kim(WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University)
• Si-Woo Lee(National Academy of Agricultural Science, Rural Development Administration)
• Young-Joon Ahn(WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University)