British Society for Plant Pathology
25th Anniversary Celebratory Meeting

Imperial College, London 19th December 2006

Past, current and future disease threats to plants in the United Kingdom

Ian M. Smith, formerly Director-General, EPPO

As an island, the United Kingdom has been particularly concerned to protect itself from the threat presented by the introduction of non-native pests (including plant pathogens). It has taken particular care to develop effective plant quarantine. Twenty five years ago, the British phytosanitary system was still more or less that inherited from the period before EU membership, with an approach akin to that of many island countries around the world, with prohibitions or severe restrictions of plant imports from most other countries. EU membership changed the system, so that by 1993 imports from other EU countries were able to enter relatively freely under the plant passport system, and imports from the rest of the world were regulated by the EU system, which applies prohibitions and restrictions in reaction to specifically identified risks. Through the 1990s, this more specific approach was reinforced by the development of the Sanitary and Phytosanitary (SPS) Agreement of the World Trade Organization, which requires members to provide, if challenged, technical justification of phytosanitary measures. Plant quarantine thus entered the world of "risk analysis", which primarily allows new pest risks to be evaluated and countered, but secondarily (and more politically) seeks to avoid trade disputes. The major problems which have arisen with the risks from animal diseases (BSE) and LMOs have also had their effects on plant quarantine, which has become more laboriously administrative and "riskaverse".

Another major development of the 1990s has been the improvement of diagnostics. Plant pathogens can be identified more readily, which is a direct advantage, but disputes about diagnosis, and the distinction between specified risky species and others, become more probable. New diagnostic techniques also make it easier to produce disease-free planting material, which in principle could move with little restriction in international trade. However, international standards are needed to back this development.

The Convention on Biological Diversity (CBD) has recently developed new agreements on the movement of alien species, which overlap to a certain extent with plant quarantine. This has led to a greater focus on risks to plants in native ecosystems, rather than in agriculture or forestry. With a greater political emphasis of the protection of the consumer and the environment, and a lesser emphasis on support for agriculture, these aspects are likely to take on more importance (though in practice risks from invasive alien plants and animals have received most attention).

These various developments over the last 25 years are illustrated by reference to individual cases of plant diseases of phytosanitary importance.