Cost-benefit of CMD research
When major food crops are severely affected by pest or disease there is understandably wide
public and scientific concern. Yet when cassava mosaic disease (CMD) first appeared in Uganda a
decade ago there was little that responsible officials could do in the country or elsewhere. In the
absence of available solutions, the disease moved swiftly, devastating much of Uganda, crossing in
to western Kenya and north-west Tanzania and posing a serious risk to other neighbouring
countries.
It was nothing less than
a pandemic. Fortunately, financial support by USAID, IDRC, the Gatsby Charitable Foundation and the
UK's Department for International Development (DFID), and research by IITA and Uganda's National
Agricultural Research Organisation (NARO) developed varieties resistant to cassava mosaic disease
(CMD) virus, funded dissemination of the new planting material and, importantly, taught farmers
about the disease and its mode of spread. Wild relatives of cassava and African landraces
contributed genes for resistance to CMD and an extra resistance to cassava green mite was also
incorporated in some of the varieties. Three CMD-resistant varieties were released originally, and
a further six more recently. Others should be available soon. What lessons can be learned from this
experience?
Long looked upon as a subsistence "poverty" crop, cassava has lacked the high profile achieved by the major cereals; wheat, rice and maize. Unlike the cereals, cassava is not grown in the major donor countries and yet this crop provides the main or significant food source for many millions of people in three continents (Africa, Asia and Latin America) in some districts contributing 60% of the food requirement.
CMD has hampered cassava production in Africa throughout this century. It is caused by gemini viruses spread by the whitefly. Affected plants are stunted and have greatly diminished tuberous root yield. But never before has an outbreak been so widespread or severe. First reported in the Lowero District of Uganda in 1988, by 1994 it had spread across 600 km of cassava growing country from the border of Kenya to the frontier with Zaire (now the Democratic Republic of Congo). During the early 1990s an estimated 150,000 ha of cassava was destroyed, some 33% of production, and this drastic reduction in food threatened household food security throughout this extensive area. In western Kenya it is estimated that the annual loss of production was 150,000 tonnes per annum valued at US$ 15 million.
Research by NARO and NRI, with technical assistance from SCRI and IITA, was supported through projects commissioned by DFID to address epidemiology, transmission, control and management. An important aspect of all the four programmes was the transfer of technology from research stations to end users: the new resistant varieties being distributed to farmers together with guidance on alternative farming practices to reduce the risk of the new varieties becoming infected with CMD. Agricultural extension staff passed on new material and new knowledge and, in turn, fed back to researchers the farmers' comments on varietal performances.
By 1998 some 95,000 ha were planted to resistant varieties with an average increase in yield of 10 tonnes per ha, giving a total increase in cassava production of 950,000 tonnes. From 1991 to 1998 total donor funding was £3 million (40% DFID) and the gross monetary benefit on this investment is estimated to have been £80 million. Other benefits have included the opportunity for Ugandan scientists to advance their professional careers and this has increased the pool of experienced researchers, making the country technically more self-sufficient. It has also resulted in IITA basing a research unit in Uganda at Namulonge, which should provide the basis for further collaborative work.
From time to time doubts are expressed about the value of funding of agricultural research, and the effectiveness of collaboration between national and international donors and research organisations. The success of the CMD control programme demonstrates that well co-ordinated research involving donors and both international and national research bodies can respond rapidly to potential crises and, by involving the stakeholders in a participatory process from the outset, can achieve lasting results with dramatic social and monetary benefits returned on investment costs.
