Precision agriculture approaches in support of ecological engineering for pest management.

Abstract

Applied entomologists have long recognised the role of homogeneous vegetation in pest outbreaks. Such outbreaks can also be brought about by the uniform application of insecticides over large areas. Pesticide applications simplify arthropod communities, impoverish them of many beneficial species and reduce their clustered distribution. Until recently, mechanised largescale crop production systems did not allow for a judicious deployment of insecticides and herbicides at a scale smaller than a field. In the last decade or so, however, new technologies have become available to allow the fine-tuning of inputs in the field, through the implementation of precision agriculture. Precision agriculture, also known as precision or site-specific farming, is a set of management practices that vary inputs spatially within a field. For the purpose of this chapter, precision agriculture is defined as the management of cropping systems at the appropriate spatial and temporal scales based on predicted economic and ecological outcomes. Thus, this definition includes ecological as well as economic criteria, and unlike most definitions also includes the temporal scale so important for insect population management. The major conceptual novelty of this cultural practice is the recognition that there is a great deal of variability within agricultural fields and that this variability results in large yield differences across the field. Accordingly, the general goal of precision agriculture is to vary management inputs in different parts of the field so that crop response (i.e. yield) is optimised. This chapter explores how the efficacy of pest control measures could be improved and adverse environmental impact be minimised by considering the spatial variability in pest occurrence and their habitat. This approach to ecological engineering makes use of new technologies that allow farmers to spatially vary inputs in the field and that are being adopted in precision agriculture. The chapter first considers the ecological effects of plant diversity and pesticide application on the density and population dynamics of insect herbivores, then describes some of the new technologies used in precision agriculture. These technologies include remote sensing (RS), yield monitors (YM), variable rate technology (VRT), global positioning systems (GPS) and geographic information systems (GIS). Finally, the applicability of these technologies, which are now used primarily for crop production, is examined in relation to the management of insect pests and weeds. The results of recent research are used to illustrate how these new tools could be used to optimally arrange crop plants in the landscape in order to reduce pest-inflicted damage. Chapter 8