tion can result from pesticides that do not reach their intended targets, precision technologies have the potential to reduce pesticide emissions into the environment and to reduce the negative side effects of pesticide use. However, precision agriculture is early in its adoption phase, and environmental benefits are not proved. Future research should focus on environmental impacts of precision technologies in the field and watershed scales (NRC 1997). The emergence of precision technologies is contributing to the increased value of information in agriculture, and it could also contribute to the value and use of agricultural management consultants who have access to data and analytical capability and can provide effective management strategies that take advantage of large bodies of information.
Satellite and airborne remote sensing data, coupled with geographic information systems and global positioning satellites, are potentially powerful tools for monitoring pest infestations and their crop impacts. Remote sensing has been effective in identifying new colonies of weeds in low-access areas and monitoring the spread of metapopulations (Lass and Callihan 1997, Lass et al. 1996, Everitt et al. 1993, Carson et al. 1995; Anderson et al., 1993). Thus, this technology can help to set priorities for herbicide application and to direct treatment to the locations where it can have the greatest impact on weed populations. In addition, airborne sensors that detect multispectral reflectance differences between crop and other vegetation canopies can identify crop-vigor variation in response to insect pests and plant pathogens (UC Davis, 1997; Baldy et al., 1996; Hill et al., 1996; Kline et al., 1996; Liedtke, 1997; Vickery et al.; 1997; Ustin et al., 1997). As this technology is improved, it is likely that pesticide use will decrease with the change from whole-field to pest-location-specific applications. Remote sensing for pest management in forest ecosystems has been widely used for several decades. Proposed improvements in application of remote sensing for pest management include increased availability of sensors, improvements in quality of images, and increased resolution of the spectral information (UC Davis, 1997).
A large number of earth-observing satellites scheduled for launch in the next few years will enable specific monitoring of environmental conditions and natural-resource management. Some commercial multispectral satellites will be collecting hyperspatial data (with spatial resolution of 1-5 m), and many others will be in resoulution range of 5-100 m. Other satellites will collect multispectral data in hundreds of bands (NASA 1998). Remote sensing is likely to become an increasingly important tool