IMPLICATIONS OF SPATIAL-DISTRIBUTION OF INSECT POPULATIONS IN STORAGEECOSYSTEMS

Integrated management of storage pests requires understanding storage ecosystems and accurately monitoring pest population levels. Geostatis tical techniques for. spatial analysis provide a powerful tool to assi st in biological interpretation of sample counts and trap captures of insects, as well as interpretation of physical measurements such as gr ain temperature and moisture content. Contour analysis is a S-step pro cess. Data are first posted to a map of sample points; then a denser g rid of data points is generated by interpolation (using one of several algorithms), and contours (lines joining points with equal values) ar e drawn at some axed interval. This provides a contour display showing the value of the variable at all points on the surface represented by the sample points. The utility of this method in stored-product prote ction is illustrated by a series of studies based on data sets for sto red corn. These include comparison of spatial distribution of species and species interactions: analysis of temporal changes in distribution , precision targeting, and evaluation of control measures; interpretat ion of trap catch; examination of physical variables and interactions of insects with the physical environment; and analysis of goodness of fit of contour surfaces to the data The utility of techniques such as grid subtraction and construction of probability contours is demonstra ted.