For some time, scientists have sought recognition of the threat that exotic pests pose for biodiversity (Liebhold et al. 1995; Niemela and Mattson 1996), and North American governments may now be starting to pay attention to this complex issue. Early this year, the US President committed $29 million in incremental annual funding to combat exotic pests. The announcement followed the removal of hundreds of trees in Chicago that were infested with the Asian long-homed beetle (Hagenbaugh 1999). This exotic timber pest spread to at least eight American states and is estimated to have killed more than a thousand trees in New York City alone.