The composition of shiso oil which showed strong repellency against the adult cigarette beetles was analyzed by GC and GC-MS. Twelve components of shiso oil were identified. The repellency of the 12 components against the beetles was investigated with an olfactometer. α-Terpineol, linalool and (-)-perillaldehyde strongly repelled the beetles at a dose of 1 μl. However, they tended to attract the beetles at a ten or hundred fold lower dose. The mixture four major components of shiso oil, (-)-perillaldehyde (60.51%), (-)-limonene (14.42%), farnesene (11.26%) and β-caryophyllene (8.47%), exhibited a strong repellency against the beetles at a dose of 1 μl, but did not repel the beetles at a dose of 0.1 μl, and attracted them at a dose of 0.01 μl. The mixture repelled the beetles at a dose of 10 μl even in the presence of the cured tobacco odor. Also (-)-perillaldehyde and (-)-limonene being, in the ratio found in shiso oil, exhibited similar repellency and attractiveness against the beetles to the four components combined.
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