The residual activity of hinokitiol used as a repellent against the cigarette beetle was investigated. When hinokitiol was placed on filter paper at a dose of 1 mg/cm2, it exhibited remarkable residual activity 24 h after the treatment. However, no significant residual activity was observed after 48 h due to rapid sublimation (90% of hinokitiol disappeared 48 h). Therefore, the development of a device in the form of repellent strips designed to affect the slow release of hinokitiol was undertaken. The strips consisted of filter paper treated with hinokitiol, a polyethylene film bilayer in which the filter paper was sealed, and an aluminum sheet sandwiched between one side of the polyethylene strip and adhesive tape. Hinokitiol was slowly released from the repellent strips through the polyethylene film. The rate of hinokitiol release was inversely proportional to the thickness of the polyethylene film. Repellent strips attached around the slits of cardboard boxes containing a food-attractant lure prevented the beetles from entering the boxes. The number of beetles in the treatment boxes was less than 20% that observed in the control boxes 64 d after making the strips. The residual activity of the repellent strips was demonstrated to last up to a maximum of 92 d after they were produced.
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