National plant protection and quarantine authorities have the mandate for protecting the resources of their countries from invasive pests entering from outside their borders. The import of seed is one among other potential carriers of unwanted pests such as people, commodities and conveyances. While prohibiting the import of seed may be an effective method of excluding foreign pests, it runs the risk of being perceived as a trade barrier unless justified by a risk analysis.
The term Pest Risk Analysis was invented by the phytosanitary community approximately ten years ago to distinguish the type of risk analysis done to support official decision making for the application of phytosanitary measures, and grew into prominence with the WTO Agreement on the Application of Sanitary and Phytosanitary measures (the SPS Agreement). A fundamental tenet of the SPS Agreement is that measures for the protection of plant, animal or human health or life are based on international standards or an assessment of risk taking into account scientific principles and evidence. The outcome is the identification of exotic pests and the implementation of quarantine security measures to guard against their accidental importation.
But the process of determining which security measures are appropriate and cost effective is a complex and, sometimes, subjective matter. One of the prime functions of risk analysis as applied to trade is to put this process on an objective basis. FAO in its publication on Guidelines for Pest Risk Analysis (ISPM Publication 2, Feb 1996; www.ippc.int) has elaborated the general requirements for a pest risk analysis. It consists of three stages: initiating the process for analysing risk, assessing pest risk, and managing risk. It is aimed at helping governments discipline their judgement on phytosanitary measures by placing emphasis on scientific evidence and principles in its analysis of risk in the international movement of seed. ISF commissioned a PRA on Erwinia stewartii in Maize.