The red banded stink bug (RBSB), Piezodorus guildinii (Westwood) has recently emerged as an economic pest of soybean in Louisiana. This species was first observed in 2000 at the St. Gabriel Research Station, located in the south central part of the state. By 2003, it comprised approximately 50% of the phytophogaus stink bug complex in soybean research trials at this location. During 2004, outbreak populations of this species occurred across south central Louisiana. By the end of that season, red banded stink bugs were present in southwestern parishes and in the northeastern corner of the state. Studies were initiated in 2006 to determine insecticide efficacy and action thresholds against red banded stink bug. In addition, surveys of native vegetation and soybean in historical soybean production areas were used to determine the range of this pest in Louisiana.