Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 8, 1997
Publication Date: N/A
Interpretive Summary: Grain and cereal products are exposed to damage and contamination by insects from the time of grain harvest until the products are consumed. Traditional methods of managing this problem and reducing losses have relied heavily on chemical pesticides, but these methods are now threatened by development of pest resistance and loss of insecticide registrations for use on stored grain and in transportation, processing and storage facilities. New methods are urgently needed to minimize pesticide risk in our environment and at the same time protect our food from loss and contamination caused by insects. An essential feature of these new methods will be an enhanced ability to detect and monitor pests throughout marketing channels and to locate infestations. This will permit timely and precision application of control measures with minimum reliance on chemicals. Scientists at the Center for Agricultural, Mewdical and Veterifnary Entomology, ARS, USDA, Gainesville, Florida, have contributed to this new technilogy by adapting methods of spatial analysis from geology to mapping distribution of insects in stored grain and in processing plants, food warehouses and retail stored. These methods will enable pest control operators to pinpoint foci of infestation for precision targeting of control measures and assessment of their effectiveness. The methods will also support development of a new generation of pest control programs that present little or no pesticide risk.
Integrated management of storage pests, with minimum use of chemical pesticides, depends on understanding storage ecosystems and on accurately monitoring pest population levels. Geostatistical techniques for spatial analysis, especially contour analysis, provide a powerful tool to assist in biological interpretation of trap catch and other sample counts, as well as interpretation of physical measurements such as grain temperature and moisture content. Contour analysis is a three- step process in which data are first posted to a map of sample points; then a denser grid of data points is generated by interpolation (using one of several algorithms) and contours (lines joining points with equal values) are drawn at some fixed interval. The utility of this method in stored product protection is illustrated by a series of case studies. These include: comparative distribution of species and species interactions; temporal changes in distribution, precision targeting and evaluation of control measures; interpretation of trap catch; physical variables, interactions of insects with the physical environment; and goodness of fit of contour surfaces to the data. The usefulness of techniques such as grid subtraction and construction of probability contours are demonstrated.