Food Security in Peril - Managing Cassava
Diseases
Author
Cassava R&D specialists, investors and partner institutions
met in Bellagio, Italy to address the growing threat to
cassava in Africa from two deadly virus diseases: Cassava
Mosaic Virus (CMV) and Cassava Brown streak Virus
(CBSD)
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Virologists
Entomologists
Breeders
Seed system specialists
Socio-economists
International development partners
CMD
• Cassava mosaic disease (CMD) is
present in all cassava growing
African countries.
• CMD is caused by at least 8 different
viruses, transmitted by white flies
and cuttings from infected plants.
• At least 45 million metric tons of
cassava are lost each year to CMD.
• A new recombinant virus exploded in
Uganda in the 90s and completely
suppressed cassava production in
the region.
Spread of the Cassava Mosaic Disease
2013
2005
2001
1997 –
EACMVUG
CBSD
• Cassava brown streak disease (CBSD)
was first described in 1935 and reappeared in East Africa in 2003,
causing a severe epidemic.
• CBSD is now the worst constraint for
cassava in East Africa.
• CBSD is caused by two viruses
transmitted by white flies and cuttings.
• CBSD is dramatic because it does not
impact the growth of the infected
plants but completely compromises
the harvest, as all the roots are
necrotic.
Spread of Cassava Brown Streak Disease
2004
2013?
2005
2009
GCP21
GCP-21 is a recognized
global organization
within the cassava
community.
GCP-21 aims to draw a
comprehensive plan to
halt CMD and CBSD and
prevent CBSD from
reaching West Africa, the
largest cassava region in
Africa.
Two questions:
1) Can we curtail spread of CMD and CBSD?
2) How should we curtail their spread?
Considerations:
1) What is known about the diseases?
2) Do we have quality planting materials?
3) How much materials can be made
available?
4) Is the institutional environment conducive?
5) Can we ensure quality for impact?
Priority 1:
Contain the CMD/ CBSD spread
in East Africa and prevent its
spread to West Africa
• Raise awareness of the risks of inter
country germ plasm movement amongst
technicians and policy makers;
• Mount a surveillance program to define the
distribution of cassava cultivation, and
varieties and abundance/incidence of
cassava white flies and viruses;
• Employ targeted best bet virus and whitefly
management strategies in new outbreaks;
• Educate high level policy makers to support
these initiatives and establish and link
national task forces on cassava virus and
white fly control
Priority 2:
Eliminate or decrease
the impact of CBSD
and CMD
• Develop/select farmers’ preferred
virus and white fly
resistant/tolerant varieties;
• Promote community based phytosanitation;
• Prioritize target zones for intervention
based on existing data and new
surveillance information;
• Develop and implement whitefly
management using biological control,
rational use for high value systems
(clean seed sites) and IPM strategies.
Priority 3:
Prevent the spread of white fly
and viruses globally
• Strengthen controls on inter-continental
germ plasm interventions;
• Update the guidelines for safe movement
of cassava;
• Raise awareness of the risks on intercontinental germ plasm movements
amongst technicians and policy makers;
• Strengthen globally capacities on cassava
value chain-related issues.
Implications for SS 1
Seed systems development
• Introduce new varieties
• Develop clean planting material
• Replace seed that has been lost
Quality control issues
• Surveillance, inspection and phyto-sanitation
• Capacity/awareness raising issues –
community level
• Field school approaches; community based
phyto-sanitation; Negative/positive selection
• Quality control through agri-business models?
Delivery channels – foundation
seed
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Willingness to pay principle
Formal (officially registered)
Informal (community based
seed producers)
Commercial (Mr. Big but
producing for whom)
Campaign based distributors
(NGOs – code of conduct,
registration of NGOs)
Seed production/distribution
• Production and protection of basic seeds
/breeder seeds;
• Specialized seed producers – getting the
markets right;
• Speed as a criterion (Tissue culture);
• Seed health as a criterion: indexing of
tissue culture materials;
• Developing economies of scale (reduced
costs from USD 1/TC to 0.5USDCents)
• Hardening – reduce losses – how do we
bulk more effectively?
THANK
YOU