Spatial distribution of stored-product insects in landscapes containing grain processing and storage facilities

The spatial distribution of pests is a basic component of the population structure. Understanding the distribution inside grain processing and storage facilities, and the scale of distribution throughout the landscape are important for a successful Integrated Pest Management (IPM) program. The spatial distribution of Tribolium castaneum and other stored-product insects were monitored inside and outside of four grain processing facilities in Kansas including a pilot feed mill, pilot flour mill, seed warehouse, and commercial flour mill. Each site contained a variety of structures and habitats within the landscape, and corrugated traps containing pheromone lure for T. castaneum and cracked wheat were placed in a grid pattern across each site. Each site was sampled for three 48-h periods in the summer of 2007 and repeated in 2008. GPS coordinates, temperature and relative humidity, surrounding habitat, and species and number of insects captured were recorded for each trap location. In 2007, the mean number of stored-product insects/trap varied between facilities and dates: ranging from 0.41+0.07 to 12.43+1.96 insect/trap. The most abundant species were: Cryptolestes spp., Oryzaephilus surinamensis, Sitophilus spp., T. castaneum, and Tenebrio molitor. Contour maps were created for the major species recovered and correlations between insect distribution and landscape and environmental factors was analyzed. For 2007 data, the major pest species showed a patchy distribution, with proximity to structures and presence of spillage most strongly correlated with distribution of pests. The results show the importance of knowing the distribution of stored-product pests beyond the structures of grain processing and storage facilities.