BSPP Presidential Meeting 2002

Plant Pathology and Global Food Security



J.G.M. Vos (CABI Bioscience) 

Farmers in developing countries contribute to local and global food security. To become successful producers, farmers need access to advisory expertise that helps them make better and more open choices about their own livelihoods. Globalisation poses a threat to smallholders in developing countries unless they get more effective support in accessing new technologies and markets, and in meeting new standards of quality and reliability. The promise of cheaper imported food needs to be balanced carefully against the threat it poses to local food producers. 

The extension role needs to move towards a mode ranging from advice and training on specific technologies to facilitation in relation to technologies (e.g. improved access) but also in relation to a wider service context (including credit, input supply, processing, marketing). The research role needs to be linked and move towards a mode of seeking to solve farmers problems and addressing their needs.  

Integrated Pest Management (IPM) is knowledge intensive. Stakeholders in the IPM knowledge system range from producers, via farmer support systems such as extension and research, as well as NGOs, industry, food chain and formal education, to national and international governments, which all have impacts on the IPM implementation at field level.  

Technologies should be developed with and validated by farmers. Farmer participatory training and research are tools to mitigate situations where farmers lack access of information. Examples are given of tackling plant disease problems through farmer participatory training and research modes. Farmer Participatory Training (FPT) focuses on transfer of knowledge through discover learning, facilitated by extension. The focus in FPT is on (1.) Identification of problem, (2.) Understanding the problem, and (3.) Informed decision-making on management. Farmer Participatory Research (FPR) focuses on knowledge generation through novel farmer experimentation, facilitated by research and extension. The focus in FPR is on meeting farmers needs and demands in appropriate knowledge generation through local technology development and/or validation. 

The focus of knowledge transfer and generation is indirectly to achieve food security, but first and foremost to improve smallholder producers livelihoods. Impact assessments show more stable production with improved product quality and increase in farmers incomes. However, for these programmes to move beyond pilot stages, it is concluded that a wider focus would be needed to involve all stakeholders in the IPM knowledge system.


Mark Holderness, CAB International, UK Centre and Phil Jones, IACR Rothamsted

Diagnostic and advisory support systems in developing countries are facing massive challenges in making relevant and effective knowledge and support available to farmers and market chains and ensuring that upstream researchers are informed of the real priority problems and issues requiring resolution.   

The global capacity to support knowledge of pathogen diversity, biology and description is eroding and its basis for sustainability is under considerable threat, yet less than 5% of the worlds microorganisms have even been described.  Growers of under-utilized crops and those of minor or local significance are further disadvantaged, as the significance of their pest problems has rarely been documented.  Developing countries bear the brunt of this diagnostic impediment, through a lack of basic capacity at all levels to describe and determine the true cause of disease problems and provide appropriate advice on their management. 

New tools are available to simplify and expedite diagnosis, but are often not  appropriate or accessible to developing country users for reasons of capital cost, skills and infrastructure availability or inadequate maintenance budgets.  Where communications infrastructure is poor, diagnostic and advisory systems may be remote from potential users, constraining their inherent accessibility and value. 

New financial models are becoming apparent, whereby principles of decentralization and liberalization, driven by macroeconomics, are creating pressure for users to directly pay for services.  This imposes its own challenges on already stretched systems, particularly where users are not in a position to directly pay for services.  The statutory roles and functions of government plant health divisions also have to be reconciled with operation of such free market principles.   

Shifts from top-down extension services to systems facilitating change create demands for diagnostic systems to be flexible and responsive to participatory approaches, where farmers are active players in developing their own solutions. 

These challenges are addressed and strategies by which they may be overcome are reviewed.  Opportunities include the use of low-cost diagnostic kits, greater access to appropriate electronic and other information resources, knowledge sharing systems, appropriate backstopping systems for local advisers, relevant training and new ways by which farmers can be more directly linked with supporting services.  Throughout there is a need for new models by which support services can be developed, made relevant and sustained within local contexts.  Examples of innovative approaches are cited from ongoing programmes in a number of developing countries and their successes, implications and constraints are reviewed.


Peter Scott (CABI, ISPP) and Stephen Rudgard (FAO)

Success in pest management, as in most walks of life, depends on having the right tools and the confidence to apply them. The key tool for disease control is knowledge. And having knowledge gives confidence. Nowhere is this more true than in developing countries.

The International Society for Plant Pathology, through its Task Force on Global Food Security, has defined an action programme with five activities. All are concerned with knowledge and knowledge transfer. A key component is extension, the subject of this session.

Examples will be given of the extension of knowledge in plant pathology at an institutional level and at the level of the grower, focusing on the key role played by information and communications technology. These will include: Teaching; Decision making; Quarantine; Risk analysis; Policy making; Economic impact. Opportunities for two-way knowledge transfer between developing and developed countries will be explored.


Eric Boa (CABI Bioscience); Jeffery Bentley (Bolivia, independent)

Plant diseases are an important constraint to achieving food security for the poorest people on the planet. These are also the people who are most remote from science and scientific knowledge, and about who plant pathologists know least. Why is it important to know more about farmer knowledge? Put simply, scientific knowledge is not enough. George Porter said there were two types of science: applied and not yet applied. Until we understand better what poor farmers do and why plant pathologists will not make the leap from not yet applied to making a real difference to farmer livelihoods.

Our paper will examine the issues concerning who knows what and how farmer and extensionist knowledge can be used to fill important gaps. We will relate experiences with farmers and extension services in Central America, South America and Asia to illustrate techniques for gathering information and synthesizing this to provide locally-appropriate solutions to disease problems. We have worked with annual and perennial crops as diverse as maize, peaches, coffee and pepper (Piper nigra).

Integrating knowledge is as much about combining experiences and understanding between researchers in the natural and social sciences as it is between researchers and farmers. Nor is farmer knowledge the only source of local information. We have examined what extensionists know about plant diseases, comparing and contrasting this with farmer and scientific knowledge (Boa et al. 2001). For example, local diagnosis of disease problems is driven by the recognition of symptoms and observed associations made by farmers (and extensionists) with supposed pest organisms.

Not surprisingly we have come across wrongly diagnosed diseases. Analysing local knowledge has allowed us to promote the correct advice for disease management through extensionists while helping them diagnose diseases in the field. Scientists cannot help poor farmers increase crop production if we dont ask them first about plant health problems. Pepper mosaic virus disease in Kalimantan is not recognized as a separate disease by local farmers. They recognize the different symptoms but dont connect them with the same disease problem.

We will discuss a new method for helping farmers which we call Going Public. Short demonstrations are held at public venues such as markets and even bus stops. The demonstrations are based on existing perceptions of diseases and pest organisms and attempt to provide new information and correct misconceptions. The Going Public approach is only one method for plant pathologists to address more directly the problems faced by farmers. Combining scientific, farmer and extension knowledge opens the way to simple yet sustainable solutions to crop health problems and increases the contribution plant pathologists make to food security.


Boa ER. Bentley JW, Stonehouse J (2001) Standing on all three legs: the tcnico as cross-cultural occupational group. Economic Botany 55 (3), 363-369

Going Public: see


Andy Maule, John Innes Centre, Norwich, UK.

Virus diseases have a significant potential economic impact on all crops. In the developed world, where production is restricted to relatively few crops on a large scale, this potential is alleviated through the extensive use of insecticides (to eliminate the virus vectors) and through the deployment of virus resistance genes. The resistance genes have emerged out of lengthy and expensive breeding programmes usually aimed at introgressing traits from related wild species. In the developing world, the challenges are more diverse, less tractable and less well supported by financial and technical resources. Nevertheless, it is in the developing world that the need is greatest. However, if careful strategic decisions are taken to achieve the most cost effective use of technical resources, biotechnology (in the broadest sense) will substantially reduce the global impact of virus diseases. Biotechnology will speed and ease diagnostic procedures to become predictive as to the durability of deployed resistance genes. Combined with a greater understanding of the population dynamics for virus vectors, it will provide additional information to allow the modelling of disease epidemics and the timely implementation of corrective management. Novel resistance genes will be identified from existing germplasm collections of domesticated and wild species. These may be introduced into elite lines through enhanced marker-assisted breeding or, conceivably by using clean approaches to gene transfer. Despite the antipathy in the developed world for gene transfer technology it has, and will continue to have, an important role in providing food security and financial stability to communities in developing countries. For many staple crops of low commercial value extensive genetic and technological resources have not been established. The use of model species for the development of novel approaches to virus resistance will help to bridge the technology gap and shorten the time for achieving sustainable virus resistance.


John Lucas, IACR-Rothamsted, Harpenden, Herts AL3 2JQ, UK. E-mail:

While transgenic herbicide and insect resistant crops have been deployed on a commercial scale in several countries for a number of years, to date trials on crops engineered for resistance to fungal pathogens have remained experimental. No doubt market as well as technological constraints have contributed to the slower progress in this area. This is now likely to change with the entry of emerging economies such as China into the GM arena. In China, more than 90% of field trials target insect and disease resistance, including diseases not amenable to chemical control, such as vascular wilts. With advances in our understanding of plant recognition and response pathways, the options for experimental manipulation of host resistance are increasing. First generation transgenic crops expressing single antifungal proteins may now be supplemented by crops engineered in defence pathways including altered regulation of the hypersensitive response. Isolation and characterisation of resistance genes is providing insights into their specificity, function and evolution. Altering R gene specificity may be possible through engineering of the ligand-binding domain, but the participation of partner proteins in the recognition step adds complexity to this approach. Conservation of certain motifs in families of R genes can aid cloning of candidate genes from species in which genome information is still rudimentary. This, coupled with the exponential increase in sequence information for most major crops, should accelerate identification of potential resistance genes. Improvements in the transformation efficiency of many crop species, notably cereals, should now allow evaluation of these genes, and their deployment, either in durable combinations or as R gene varietal mixtures. The function and durability of genes for "non-host" resistance might also be evaluated by this approach.


John M. Whipps, Horticulture Research International, Wellesbourne, Warwick, CV35 9EF

Biotechnology is gradually playing a more important role in the development of biological disease control. Areas involved include molecular biology and inoculum production, formulation and application procedures. Molecular biology has been used to 1) examine modes of action of biocontrol agents (BCAs) and their significance in efficacy, 2) helped to confirm or establish identity of BCAs, and 3) aided in ecological studies of BCAs. These are all key data required for registration. In some cases, these technologies have been applied to BCAs that have become commercial products. For example, the Agrobacterium radiobacter Tra- deletion strain, K1026, sold in Australia for crown gall control. Genetically modified plants expressing disease resistance are also being developed. Inoculum production, formulation and application are particularly important features in the development of a BCA as it is often during these procedures that cost-effectiveness and commercial potential are realised. Important advances, particularly in solid state fermentation, have been made in these areas recently. Significantly, there are now over 80 bacterial and fungal products on the market or undergoing registration with disease control capabilities and, for the majority, biotechnology has played an important role in their development.


Margarita Escalier and Paul Teng

Developing countries are characterized by predominantly rural populations, which face increasing pressures to grow more food, feed and fiber under constraints of water, arable land, timely labor, and often, access to inputs such as fertilizer and seed. In the foreseeable future, these constraints are anticipated to worsen and in Asia, which holds > 60% of the worlds population, demographic changes will lead to fewer farmers feeding more people in "Megacities". There is an urgent need to increase agricultural productivity and total production, especially at source since most of the major food grains are consumed where they are produced. For example, the International Rice Research Institute estimates that only 2-4% of total rice production are available for global trade, with the remaining > 90% of production consumed within Asian countries. Biotechnology is one research tool set which scientists such as Norman Borlaug and Gurdev Khush, have suggested, is essential to develop the new crop varieties needed to yield more with lower inputs, and able to have greater tolerance to various pest types and to abiotic stresses. One product of the application of biotechnology is genetically-modified (GM) crops expressing useful traits. The adoption of genetically modified (GM) crops by farmers has been one of the most spectacular examples of adoption of a new technology in recent global agriculture. GM crop area increased to >52 Million ha in 2001 from its year of commercial introduction in 1996, and now accounts for 36%, 16%, 11% and 7% of global area of soybean, cotton, canola and maize, respectively. The trend graphs show that developing countries have increased their rate of increase of planting and it is anticipated that future increases will come relatively more from developing than developed countries as the large pipeline of GM crops undergoing field testing by private companies and public institutions are approved for commercialization. Currently, GM crops are commercially grown in fourteen countries, and are being field tested in twice that number. The main biotechnology traits are herbicide tolerance, insect resistance, and disease resistance. Some of the developments underpinning these global statistics are even more impressive. For example, in Hebei Province in China, within its first year of introduction, B.t. cotton achieved a 90% adoption rate (> 2 Million smallholders) and reduced insecticide use significantly while giving farmers more income. In Asia, all counties with a modern agricultural R & D capacity have transgenic plants under contained conditions and the supporting biosafety regulations for their field testing. Data from plantings of B.t. cotton by smallholders in the Makhathini Flats of South Africa, in Mexico, and in Indonesia all confirm the direct benefits to these farmers through increased income and decreased exposure to insecticides, as well as neutral to positive effects on non-target organisms. The success in transferring this useful technology to farmers has been achieved in some countries in spite of systematic attempts by environmental and other groups to discredit it. The benefits from agricultural biotechnology for the smallholder farmer in developing countries are many and may be expected to receive more recognition from the public in the future. While the current GM crops contain mainly agronomic traits and are therefore of direct benefit to farmers, it is anticipated that in the near future, GM crops with improved nutrition and health-enhancing traits will be available, such as "Golden Rice". With improvements in the public knowledge, and in the regulatory systems to assure safety, GM crops are anticipated to play a key role in food security and economic development of many developing countries.