Seasonal catches of the bean bug, Riptortus clavatus (Thunberg) (Heteroptera: Alydidae), in water-pan traps with synthetic attractants

Seasonal catches of the bean bug, Riptortus clavatus (Thunberg), in water-pan traps with synthetic attractants were compared with the seasonal prevalence of this insect estimated by direct counting in. soybean fields in 2002 and 2003. Eight traps were set at various locations to evaluate the effect of the environment of trap location on the number of catches. In the soybean fields, the peak incidence of this insect occurred in early September when the soybean pods began to enlarge. In contrast, the number of catches in traps reached a peak one month after the peak incidence in the soybean field. These results demonstrate that the number of trap catches does not reflect bean bug incidence in soy bean fields. The number of trap catches at eight locations differed largely, and the factors that affected the number of bugs trapped remained unclear. To achieve the practical use of synthetic attractants for monitoring the population of this insect, further studies are needed to gain information that links the density of this insect in soybean fields and the number of catches per trap.