The Science of Risk Assessment for Phytosanitary Regulation and the Impact of Changing Trade Regulations

Abstract

I exotic or alien species cause enormous damage to the natural environment. Indeed, 49% of all imperiled species in the United States are threatened in part by alien species (Wilcove et al. 1998). The toll may be even higher: Additional plant species have been harmed by alien species but have not yet been designated as imperiled (e.g., the American chestnut, Fraser fir, American elm, flowering dogwood). Losses in the agriculture, forestry, and other sectors of the US economy and control costs associated with invasive alien species total $137 billion annually. Approximately $80 billion of that amount is associated with alien plants, insects, and disease pathogens subject to phytosanitary regulations (Pimentel et al. 1999), which are the subject of this article. Because attempts to eradicate established invasive alien species have met with little success, scientists recommend that governments put the highest priority on preventing introduction of such species. This article examines US policies governing the structure and implementation of prevention programs aimed at alien plants and those insects and disease pathogens considered to be plant pests.