Spatial analysis of pheromone-baited trap captures from controlled releases of male indianmeal moths

Early detection and precision targeting are key elements in a successful management strategy of stored product pests so that actions can be implemented while the population density is still low and controllable. The overall purpose of pheromone trapping is not to catch as many insect pests as possible, but to obtain monitoring data that provide as much information as possible about the spatio-temporal dynamics of the pest population. We placed 30 pheromone-baited traps in a grid with traps being 3-4 m apart in a relatively small trapping space with (1) no food, (2) no human activity, (3) all traps placed at the same height, and (4) no presence of Plodia interpunctella females (except when used as lures). Male moths were released from single locations, and the purposes of this study were to (1) evaluate the trapping efficiency (number of male P. interpunctella caught) when using different (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Oac) (ZETA) concentrations in lures, (2) release male R interpunctella individuals from single locations and determine the relationship between pheromone-baited trap captures and distance from the release site, and (3) describe the spatial distribution pattern of pheromone-baited trap captures. The main conclusions were that (1) total trap captures of male P. interpunctella individuals were similar when deploying ZETA concentrations in lures ranging from I to 2,000 mu g, (2) there was a significant exponential negative relationship between trap captures and distance from release sites when using live P. interpunctella females, 50 mu g, or 500 mu g as attractants, (3) the location of trap capture centroids was similar for trials with random and aggregated spatial distributions, (4) independently of pheromone concentration, most trap capture centroids were located within 3 in from the release site, and (5) even in a highly simplified environment, there was considerable difference in the spatial trends from three different release sites.