“Game changing technologies” needed to fight cassava diseases

9 June, 2013 by (comments)

Alarming outbreaks of two devastating cassava diseases in Africa have prompted an alliance of experts to make an unprecedented international commitment to tackle them.

Members of the Global Cassava Partnership for the 21st Century (GCP21) announced plans for the sweeping set of measures to impede the spread of the flesh-eating cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) both within the continent and beyond.

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According to an official statement released by the group following its conference in Bellagio, Italy, last month, measures include the development and deployment of “game changing technologies” to produce more disease-resistant plants, to better understand cassava viruses and the whiteflies that transmit them, and to improve systems for monitoring outbreaks and distributing virus-free plants. The statement, endorsed by GCP21 participants, also calls for critical gaps in research funding and information to be addressed in order to improve the resilience of cassava – a vital staple crop that feeds close to 300 million Africans, and relied on by hundreds of millions more in Asia and Latin America.

In terms of specific threats, conference participants agreed the challenge of the rapid spread of CBSD – relatively obscure until a decade ago – as the highest priority for research and awareness-raising. The disease, which destroys cassava roots underground – sometimes wiping our entire harvests – has already spread from Uganda, Kenya and Tanzania to parts of DR Congo and possibly Angola, en route for the world’s largest producer and consumer of cassava, Nigeria, as reported on the CIAT blog recently.

Participants agreed to redouble efforts to: raise awareness of the risks of spreading CBSD through moving uncertified cassava stakes for planting; establish a detailed surveillance program to track the spread of CBSD; and deploy some of the most promising technologies for controlling the viruses and whiteflies in areas with new outbreaks and those at imminent risk. Developing a system for producing and distributing high quality, virus-free cassava cuttings through national and international research centers, NGOs, the private sector and village communities, was identified as a top priority.

“These diseases constitute a crisis of enormous proportions with the potential to unleash severe human suffering,” said GCP21 director Claude Fauquet. “If CBSD reaches Nigeria it would cause a human catastrophe of unforeseen magnitude; if it reaches Thailand or India it would jeopardise economic sectors worth billions of dollars a year. That’s why an agreement of this nature and scope is unprecedented in the history of cassava research and clearly reflects the growing recognition of the huge importance of cassava in Africa – for food security, for incomes, and for development.”

The agreement will be the basis for a formal road map for tackling cassava pests and diseases, which is expected to be finalised in July.

CIAT will have a crucial role, as coordinator of a global initiative to sequence the cassava genome. Partly funded by the CGIAR’s Roots, Tubers and Bananas research program (RTB), and with the support of a host of international partners, work is already underway to sequence the entire collection of global cassava varieties, as part of a multi-million dollar search for valuable traits including sources of resistance to cassava diseases and the insects that transmit them. CIAT’s gene bank at its headquarters in Colombia is one vital source of cassava varieties to be sequenced, and all 5,000 varieties known worldwide should be sequenced by 2017.

“When it comes to finding the genes responsible for resistance to these diseases, it’s not a matter of if we get the call, it’s a matter of when,” said CIAT’s Luis Augusto Becerra, leader of CIAT’s cassava genome sequencing work. “Then we can begin the process of developing improved cassava varieties for farmers to grow, safe in the knowledge that the threats of brown streak or mosaic disease will be a thing of the past. That makes the work tremendously exciting because it will benefit hundreds of millions of people.”

CIAT will also work on tackling diseases not currently present in Africa, but which pose a threat if introduced, such as frog skin disease, a major cassava constraint in Latin America.

“Cassava diseases are the main obstacle in the way of cassava fulfilling its enormous potential, so this is a landmark agreement,” said Joe Tohme, leader of CIAT’s Agrobiodiversity research area, and joint founder of GCP21. “If you want to have a serious impact on rural livelihoods in Africa, you have to be working with cassava and cassava producers, and tackling these diseases is one of the most effective ways. But this must include work outside Africa to make sure we are well-prepared as possible for new pest and disease threats.”


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Filed Under: Africa @en, Asia @en, Cassava @en, Crop diversity, Crops website, Latin America and the Caribbean