Submitted to: Potash and Phosphate Institute Guides
Publication Type: Popular Publication
Publication Acceptance Date: 10/17/2007
Publication Date: 10/17/2007
Citation: Park, Y., Ellsbury, M.M., Krell, R.K., Tollefson, J.J., Pedigo, L.P., French, B.W. 2007. Spatial variability in corn and soybean insect pests: precision farming and insect pest management for the future. Potash and Phosphate Institute Guides. Available at: http://www.ipni.net/ssmg. SSMG-27.
Interpretive Summary: This article was written to summarize the state of the art regarding site-specific management for two major insect pests of corn and soybean. Contributions from research at Iowa State University, Ames, Iowa and from the North Central Agricultural Research Laboratory, of USDA, ARS at Brookings, South Dakota are included. Despite the potential benefits of site-specific insect management, there are significant barriers to implementation of precision IPM, primarily the high cost of obtaining site-specific information about insect pest populations. The cost of manual sampling and scouting in terms of labor and time is a serious constraint to obtaining data at the intensity necessary for accurate characterization of spatial variability in pest populations. Ideally, a capability for real time in-field decision making would allow immediate implementation of timely management practices. Remote-sensing technologies linked to GIS/GPS technology offer great promise for near real-time monitoring of pest populations to facilitate map-driven application technology. Digital aerial photography or satellite images offer great potential for identification of insect-stressed plants in areas that may be targeted for intensive sampling. Targeted sampling of insect pests that concentrates on high risk areas of a field may help reduce the number of samples required. The second barrier to implementation is the lack of equipment capable of site-specific insecticide application. Insecticides are the most effective control method for most soybean insects when populations exceed the economic threshold. This presents a problem in soybean because late-season insecticide treatments usually are done by aerial application. At present, the technology capable of aerial site-specific insecticide applications is not commercially available. In the corn system, most insecticide application equipment is designed for planting-time application, well before assessments of early-season rootworm activity are feasible. With precise knowledge of probable pest distribution, site-specific insecticide applications might be possible at planting time for corn rootworm larval control using maps of the previous season’s adult densities as input for a GIS to drive computer control of Smart Box ™ applicators.
Technical Abstract: Public and private research effort is being invested in site-specific insect pest management but progress in this area lags behind other aspects of site-specific agriculture. The existence of field-level spatial variability in populations of key pests of soybean and corn suggests that a site-specific approach to IPM is possible. The necessary GIS/GPS capabilities are available but have not been effectively combined into platforms incorporating economical scouting systems or real-time monitoring and mapping of pest variability. It has been suggested that optical sensors might be applied to detection of canopy-dwelling insect pests such as the bean leaf beetle. Targeted sampling can be directed by analysis of remotely sensed aerial images that identify anomalous areas indicative of severe pest infestations, provided the cost of the imagery can be kept at reasonable levels and still provide rapid turn-around. It will take time to overcome the barriers associated with site-specific insect management, but because of the potential benefits of this technology, research in this area will continue to move forward.