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Risk assessment and surveillance for prevention of crop pest outbreaks - a new model for Africa

Maize Lethal Necrosis has spread across East Africa (© Fera)
Maize Lethal Necrosis has spread across East Africa
© Fera

African agriculture is vulnerable to newly introduced diseases or diseases with new virulences. In the context of East Africa over the past few decades, major crop diseases such as Cassava Brown Streak Disease (CBSD), Banana Xanthomonas Wilt and Maize Lethal Necrosis have spread across the region causing major food loss and uncertainty in markets. Most recently, Fusarium Wilt Tropical Race 4 on banana has been reported in Africa (Mozambique) for the first time. These diseases affect staple crops that are critical to African food security. Moreover, the resulting uncertainty from such shock events discourages long term investment by farmers and food chain stakeholders, undermining positive change.

Looking to the future, in the face of climate change, greater volume and diversity of trade and a more dynamic population, the risk of pest and disease outbreaks can only be expected to rise. Julian Smith of the Food and Environment Research Agency (Fera), who recently led a webinar 'Getting Ahead of the Crop Pest Epidemic Curve' with FARMD, puts forward the case for a new model for crop pest risk assessment and prevention in Africa.

Problem analysis

CBSD (© Fera)
© Fera

To prevent pest epidemics, early warning for timely intervention is essential. However, traditional models of crop pest surveillance and response in Africa have largely failed to deliver. In this realm, the operating of plant health systems through a central government hub appears to create a spatial and temporal gap with events taking place on the ground.

A solution is to devolve plant health services to the community and to the private sector, while maintaining government bodies in an oversight role. Under this model, surveillance costs are shared in a form of public-private partnership to make the system more sustainable. However, to establish such a system, three main innovations are needed: new, diagnostic tools for crop pests that allow for non-specialist and decentralised use; community and private sector engagement and use of ICT for reporting; and institutional strengthening at national and regional scales.

A new model for plant health provision

Step 1 - Decentralised pest and disease detection

Recent developments in diagnostic technologies are already making decentralised testing a possibility. Lateral flow devices (LFD) - a 'dip stick' type diagnostic indicator - are just one type of testing tool that offer greater flexibility in use, with lower cost and technical demands. In Uganda, for example, an LFD has been used to detect cassava brown streak viruses. In developed countries, similar devices are increasingly in use for plant, animal and human health.

Step 2 - Community surveillance for real-time monitoring of pest outbreaks

Community surveillance for CBSD in DRC (© Fera)
Community surveillance for CBSD in DRC
© Fera

Pest and disease surveillance involving the community represents a largely unharnessed potential. A success story comes from the Democratic Republic of Congo, where community surveillance was used to provide the first authenticated CBSD disease identification for the country. Led by Fera and Catholic Relief Services, and based on CABI's plant clinic approach, NGO staff shared images of cassava disorders with market-goers, in order to learn what problems they were experiencing with their crops. From this raw, substantial and quickly gathered data, a number of suspected CBSD cases were identified and followed-up with farmers to obtain plant samples for laboratory verification. This approach provided a valuable, 'real-time' picture of pest events in the area but also showed that the disease was not as common as feared.

It was apparent from this example that farmers and other stakeholders are keen to be part of the solution to pest reporting when this is linked to advice for producing a healthy crop. Moreover, using digital photographs taken on mobile phones, these can be shared 'upwards' to the government for checking and analysis. Looking at financial sustainability, it may be that plant clinics could be embedded within the commercial interests of local stockists and agricultural agents, such as agro-input suppliers. The case for such community-based surveillance, underpinned by a commercial sector and linked with government, is compelling.

Step 3 - National and regional policy focus

Crop pests and diseases do not respect national borders, so building a strong, regional community of plant health institutes - National Plant Protection (NPPOs) and Regional Plant Protection Organisations (RPPOs) - is vital. But these institutes need to maximise their value by focussing their resources on their most critical functions, which they alone are able to deliver on. Thus devolving responsibility for surveillance should be viewed positively, in allowing them to focus on more complex matters of evidence and policy. Indeed, it is a step that government plant health bodies of developed and developing countries alike must take, whilst retaining oversight of the devolved activity.

Banana Xanthomonas Wilt in Uganda (© Fera)
Banana Xanthomonas Wilt in Uganda
© Fera

To deliver on the NPPOs and RPPOs' role, support is needed to build durable functional capacity, which will only be achieved by long-term professional development and engagement with like-mandated institutes across the world. A good example is evident in how the European Union has supported new member states with its 'twinning' approach for plant health (amongst other government functions) that involves the mentoring of existing and new member like-mandated institutions over a period of years. Steps to achieve a similar model for East Africa can be seen with the Kenya Plant Health Inspectorate, which is registered as a Centre of Phytosanitary Excellence with COMESA, providing support to neighbouring countries.

At a regional level, the European Food Safety Authority (EFSA), which functions through a small core staff and a team of call-down experts, provides fast, independent access to expert judgements in advising policymakers. Europe also has a mechanism for coordination of phytosanitation funding (EUPHRESCO), which serves to add value to country investments, whilst also working at a regional scale.

Reform deserves priority

There is a strong argument that African agricultural failings are not essentially about knowledge gaps or research needs: they are about the failures of systems, processes, planning and pre-emptive action. What is needed is better organisation; strengthening what is already in place, enabling innovation to take hold, and being prepared to prevent shock events. Current systems amount to a 'market failure' in providing the necessary support to farmers, traders and consumers. The traditional roles of the national plant institute need re-defining, recognising the potential in the commercial sector and the community. Given the rising threat from crop and pest epidemics - as documented in this edition of New Agriculturist - the need for reform has never been more urgent.

Date published: January 2014


Have your say

Great model that could prevent disease spread. (posted by: Bramwel Wanjala)


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