The tobacco beetle (Lasioderma serricorne) is a notorious pest in stored tobacco. Pheromone traps have been used as a monitoring tool to prevent infestation with the beetles. They should be placed in accordance with a certain installation method to correctly grasp the situation of a site, factory or warehouse, and a method for each pheromone trap is usually fixed by each manufacturer of pheromone traps. An interval between traps is one of the important parameters related to trap installation. A recommended interval of NEW SERRICO, a pheromone trap for the tobacco beetle, is 10 m. However, traps are not always placed at 10 m intervals at a site. The purpose of this study was to clarify influence of intervals on trap efficacy.

NEW SERRICOs were placed at 10 m intervals in a warehouse (20 x 20 m). Three hundred male beetles were released from one point in a room. The catches were counted one week after release. This experiment was replicated three times. A series of the experiments was conducted for traps at 5 m and 20 m intervals. All released experiments were carried out from July to September.

Total catches of all traps at 5 m intervals was the maximum, because the number of traps in a warehouse was the most. But average catches per trap was not different among three placement patterns. It indicated that efficacy per trap is constant regardless of the number of traps in a room.

The results suggest that it is possible to adjust an installation interval with a focus on 10 m depending on the situations of factories or warehouses; nevertheless the interval of 10 m is still recommended, considering that the infestation source is first detected from monitoring data.