Study of the Grasshopper Integrated Pest Management Project'

The Grasshopper Integrated Pest Management Project (GHIPM) WDS a S15 million projccllhat lasted from 1986 La 1994 to identify, develop, and implement rangeland grasshopper management tactics within the Framework of Integrated Pest Management (lPI\'I) in the western United Stales. Computer simulation has been used La fulfill many original objectives for GHIPM and help bridge the gap between theory and practice. One group of computer simulation studies was developed to probe basic mechanisms of rangeland grasshopper ecology. For example, an objecl.()ricnted simulation is being developed that can represent any number of unique grasshopper cohorts for specific species, life stages, and disease st..:,tus. Soil temperature and moisture are also being simulated to support a grasshopper egg hatch model. These research models were designed for basic science with a focus on improving management of rangeland grasshoppers. Another group of models has been developed nndlor used to simulate grasshopper population dynamics, forage growth and destruction, and ranch economics for essentially all rangeland areas in the western United Stnt.cs. These models nrc used in a computer decision support system called Hopper to structure and provide knowledge to land managers who mAke decisions about grasshopper conLl'o1. Hopper provides objective analyscs of management options including innovative rPM strategies that could not be effectively evaluatcd in the past. The devclopment of Hopper and suppor·ting models has caused D paradigm shift from the goal of maximizing control mortality to the lPM goal of optimizing economic, environmental, and social values. Hopper was adopted in 1994 and is used to evaluate all fcderal programs for rangeland grasshopper management. Now the scope of grasshopper management. includes lechniques that. mayor may not. cause grasshopper mortality. For example, modifying cattle herd size and grazing management strategies may allow the IPM goal to be reached better than control options. Also, reduced control and the associated reduction in cost from a reduction in pesticide used for control can sometimes provide the best economic return in addition to other longcr tenn benefits. Computer simulation within Hopper has provided the nexibility to apply [PM to a complex of grasshopper species over a gcographically very large and ecologically diverse area.