A push-pull strategy for controlling Riptortus pedestris (Hemiptera: Alydidae) using host plant semiochemicals

Riptortus pedestris is a major pest of soybean in East Asia that feeds on maturing seeds, reducing nutritional quality and causing seed abortion. Aggregation pheromone of the bean bug has been conventionally used as a lure for mass-trapping, but the control practices, used by farmers and recommended by the manufacturer can increase infestation in soybean fields. Here we investigated the efficacy of soybean semiochemical blend as a repellent incorporated with an attractant blend to develop a push-pull strategy. The efficacy of potential repellents was tested in a soybean field by evaluating three control strategies: a potential repellent (push), an attractant based on the synergistic effect of synthetic host plant volatiles and the aggregation pheromone (pull), and a combination of the attractant and the potential repellent. We adopted two different monitoring systems, sticky traps and camera traps, to assess the spatial distribution of the bean bugs. The attractant and repellents were strategically deployed, by putting the repellent in the center of soybean plot while the attractants were placed at the edge of the plot. In soybean plots treated with only attractants at the edge, the number of bean bugs was significantly higher in both soybean and edge areas than those of control plots. In contrast, the number of attracted bean bugs to soybean area significantly decreased in the push-pull treated plot, verified by both sticky trap and camera trap methods. This strategy could prevent colonization and population establishment of the bean bugs in soybean fields as part of an integrated pest management.