British Society for Plant Pathology
25th Anniversary Celebratory Meeting

Imperial College, London 19th December 2006

The global impact of plant diseases

Peter Scott

BSPP was born 25 years ago because Britain had no professional society devoted to plant diseases and their impact. In fact BSPP had to be born, because the societies closest to plant pathology couldn't agree on who should manage the journal Plant Pathology, with its practical emphasis on mechanism, impact and management of plant disease. The impact of plant disease is everywhere, and is inadequately appreciated by policy makers - something which immediately suggests a role for BSPP. Considering food crops alone, the 14 staples are subject to more than 100 principal diseases, and to a total of thousands. At least 10% of global food production is thought to be lost to plant disease. Though this estimate lacks a strong base, such losses must make a huge global impact when, according to the World Bank, more than 800 million people do not have adequate food, and more than 1 billion live on less than $1 a day.

The most serious impacts in human terms occur in developing countries, which provide innumerable examples of damaging pathogens of crops and forests, with serious impacts on food security. Impacts in industrial countries may be less obvious, because of better management and because there may be food surpluses, but substantial costs are still incurred. Plant diseases have shaped history: the impact of potato blight in Ireland in the 1840s was starvation for around 1 million people, while more than 1 million attempted to emigrate. In the US, the southern corn leaf blight epidemic of 1970-1 did not cause starvation but threatened the whole corn industry, through its dependence on a narrow genetic base. Equally serious is the poorly quantified ongoing impact of the thousands of species of fungi, bacteria, viruses and oomycetes on crops, forests and wild plants that we plant pathologists live by. It would be a mistake for the discipline of plant pathology to thrive primarily as a field of study for molecular biology, powerful though this is in understanding plant disease. The BSPP recognizes also that plant disease has economic and environmental impact that truly matter in social and economic terms. The International Society for Plant Pathology (ISPP) has a Task Force on Global Food Security with a small programme aimed at influencing public opinion and policy. It is exploring the development of a new journal, which may be called the Journal of Food Security.

Plant diseases are here to stay. We can dream of a world without them, but natural selection will ensure that it remains a dream. BSPP, from its position of authority as a science-based organization, will have much to attend to during its next 25 years. Raising awareness of the impact of plant disease is a critical - and challenging - place to start.