Monitoring of Tribolium castaneum (Coleoptera: Tenebrionidae) in Rice Mills using Pheromone-Baited Traps

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a common pest in rice mills. With limited information in the literature addressing T. castaneum in rice processing facilities, we examined the spatial and temporal distribution of T. castaneum inside and outside of three commercial rice milling facilities and one rice packaging plant from June 2012 to August 2014 using pheromone-baited dome traps. Each mill had very different population trends with fewer numbers collected in rough rice storage areas. T. castaneum were more commonly collected in processing areas. Beetle infestation at all the mills was evaluated using the threshold of mean beetle capture of 2.5 beetles per trap per 2 wk period. Trap captures were below threshold for all but one facility. Temperatures inside were ~1°C warmer than outside temperatures, with these temperature differences more noticeable during cool months (October-March). Higher numbers of T. castaneum were captured in 2012 in comparison to 2013, with higher beetle numbers observed during warmer (April-September) than cooler months. With variation in trap capture of T. castaneum occurring among all facilities, this study illustrates that having a monitoring program designed for each facility is important to help managers decide when and where to apply pest management tactics. The use of pheromone traps could provide information to mill managers to find locations within a mill that are most vulnerable to infestation by T. castaneum, and to assist with the timing of control interventions.