A Model for Probabilistic Assessment of Phytosanitary Risk Reduction Measures

The World Trade Organization (WTO) Agreement on Sanitary and Phytosanitary Measures (the “SPS Agreement”) seeks to ensure that SPS measures do not result in unnecessary barriers to international trade by requiring that countries establish or maintain SPS measures on the basis of scientific risk assessment (11). Given the downward pressure on international trade tariffs and agricultural subsidies resulting from the 1994 conclusion of the Uruguay Round of the General Agreement on Tariffs and Trade (GATT), many observers expect SPS measures to be a growing area of trade disputes as countries seek to protect their producers from international competition. An SPS restriction can be a very effective protectionist device and, because of its technical complexity, a particularly deceptive and difficult barrier to challenge. At the same time, however, the SPS Agreement acknowledges the legitimate use of SPS measures (which include laws, regulations, and procedures such as inspection and treatment) to restrict trade to protect against bona fide risks to human, animal, and plant health. The SPS Agreement calls for the widest possible international harmonization of SPS measures. With respect to phytosanitary measures, the SPS Agreement identifies the international and regional organizations operating within the International Plant Protection Convention (IPPC) framework to promote the harmonization objective. The SPS Agreement permits a member to introduce or maintain SPS measures that result in a higher level of protection than would be achieved by relevant international standards if the member determines, on the basis of a risk assessment, that the international standards are insufficient to achieve the level of protection the member determines to be appropriate. Nevertheless, the SPS Agreement obliges members to ensure that such measures are not more trade restrictive than required to achieve their appropriate level of phytosanitary protection, to avoid arbitrary or unjustifiable distinctions in the levels of protection deemed appropriate, to accept as equivalent alternative SPS measures demonstrated to achieve the appropriate level of protection, and to make transparent the determination of the appropriate level of sanitary or phytosanitary protection. Wood-inhabiting pests of quarantine importance include the Asian longhorned beetle (Anoplophora glabripennis) and pinewood nematode (Bursaphelenchus xylophilus). A woodboring insect native to China and Korea, the Asian longhorned beetle commonly infests living, healthy trees. In 1998, after detection of Asian longhorned beetle infestations in urban hardwood populations in New York and Illinois, the United States Department of Agriculture (USDA) promulgated an interim rule adding treatment and documentation requirements for solid wood packing material (SWPM; e.g., pallets and crates) from China. It is estimated that between one-quarter and one-half of China’s exports to the United States (valued at $42 billion in 1999) were affected by the change (3). The pinewood nematode infects conifers, especially pines, and is vectored by pine sawyer beetles of the genus Monochamus. The pinewood nematode is indigenous to North America, where it is rarely a primary pathogen, but it has caused extensive mortality in pines in Japan. The European Union (EU) began regulating U.S. and Canadian shipments of unprocessed coniferous wood products in the early 1990s, following interceptions of the pinewood nematode in shipments of wood chips to Finland and Sweden. European concern over the pinewood nematode subsequently heightened after an outbreak in Portugal and interceptions of the nematode in SWPM from the United States, Canada, China, and Japan. In 2001, the EU adopted emergency measures requiring the treatment and marking of all coniferous nonmanufactured wood packing material originating in the United States, Canada, China, or Japan. EU imports from the United States were valued at approximately $150 billion in 1999, and the USDA expects that a significant portion of U.S. exports will be affected by the measures, because most goods are transported using SWPM and a substantial portion of pallets and containers are made entirely of or partially of coniferous lumber. It is estimated that well over one-half of the $1.7 trillion worth of goods that entered or left ABSTRACT Powell, M. R. 2002. A model for probabilistic assessment of phytosanitary risk reduction measures. Plant Dis. 86:552-557.