Effect of the Size of Openings of Pheromone Traps on the Capture Efficiency of the Rice Leaf Bug, Trigonotylus caelestialium (Heteroptera

The SE trap® is considered unsuitable for monitoring the rice leaf bug, Trigonotylus caelestialium, because of its low capture efficiency. One of the reasons for this low efficiency is that the opening size of this trap is assumed to be too small for the males to reach the sticky plate. We therefore improved the SE trap to widen the openings. Specifically, a pillar was placed at each corner between the roof and the bottom plate, and the entrance area was varied through the length of the pillar (i.e., 5 cm, 10 cm, and 15 cm). In paddy fields, the average number of males captured per trap increased with the length of the pillar. The average number of males captured in traps with pillars 10 cm or 15 cm long was not significantly different from with a vertical sticky trap, which is generally used as a pheromone trap for this bug. The results suggest that these improved traps may be a useful alternative to the vertical sticky trap.