Determining the attractive distance of Mexican rice borer (Eoreuma loftini) pheromone traps in rice agro-ecosystems

The effect of intertrap distance on the number of male Mexican rice borers, Eoreuma loftini, captured was assessed with hexagonal arrays of pheromone traps with a single trap in the center.  Arrays with intertrap distances of 5, 25, 50, 100 and 250 m were deployed in rice fields on two farms in Jefferson and Chambers Counties, TX, and the number of moths caught was recorded for 5 sampling periods in 2011.  Differences were detected between treatments, with the greatest numbers of E. loftini caught in traps spread 250 m apart.  The proportion of the total moths caught by the center trap was lower than the average proportion caught in perimeter traps at 5, 25, and 50 meters.  The study was repeated in Calcasieu Parish, LA in 2013 with intertrap distances of 50, 100, 150, 225, and 300 m.  Mean catch/day increased with intertrap distance.  The proportion of moths caught by the center trap was significantly less than perimeter traps in arrays with distances of 50, 100, and 150 m. Results indicate there is substantial interference between traps placed <100 m apart, and the attractive distance of E. loftini pheromone traps is likely 100-200 m.