摘要：Invasive weeds are a large problem on large tracts of rangeland in North America. Biological methods of control have been instituted, but many information gaps remain. An investment model approach is used to demonstrate some of the potentially key pieces of biological data that are required for an analysis. This model is applied to the control of leafy spurge on rangeland. The results of control are very dependent on the rate of spread and control by the biological control agent, the initial density of the weed, and the recovery of the forage (grass) after the weed has been controlled. Benefits of control are relatively low, as is the cost of the biological control practice. It takes several years before net benefits of the control practice are positive.
