Cassava mosaic: a new threat to Burundi's emerging peace

credit: James Legg

As the final votes were cast in the recent successful multi-party elections in Burundi in Central Africa - offering hope for an end to 12 years of civil war - reports emerged of a quite different threat to the security of Bujumbura, the nation's capital city. From the fertile plains and the slopes of the mountains surrounding Bujumbura, farmers have observed dramatic changes in their fields. Symptoms of yellowing, leaf loss and stunting indicate that the virulent pandemic 'cassava mosaic' virus disease (CMD) has continued to spread.

Cassava, a key staple for many Burundians, has been under attack from CMD since 2002. Symptoms were first noticed in the northern provinces of Kirundo and Muyinga. The disease has continued to spread rapidly through the heart of the country, devastating yields so that most farmers have simply abandoned the crop. The UN's Food and Agriculture Organization (FAO) estimates that the epidemic has contributed to more than 40 per cent losses in northern provinces, and may increase still further as the epidemic spreads to the south and west. Moreover, trade has been hit, as supplies of cassava products (fresh roots, dried chips and flour) have dwindled in both rural and urban markets, and prices have more than tripled.

An old enemy

credit: James Legg

Cassava mosaic disease is not new to the region. Its impact has been felt in many of Burundi's neighbouring countries , including Rwanda, Democratic Republic of Congo and Tanzania. An epidemic of an unusually severe form of CMD was first noticed in northern and eastern parts of Uganda in the late 1980s resulting in widespread food shortages and localised famine. From these threatening beginnings, the disease spread to cover much of the prime cassava growing belt of East and Central Africa, reaching westwards as far as Gabon.

In a desperate race against time to mitigate the impact of the pandemic, scientists from the International Institute of Tropical Agriculture (IITA) and the UK's Natural Resources Institute (NRI), have criss-crossed the region to monitor disease spread and co-ordinate management efforts. DNA fingerprinting techniques have helped to track the virus, forecast potential spread of the epidemic and identify worst-affected regions. "We are having to deal with a crop plant problem equivalent to the HIV/AIDS crisis," says IITA/NRI's James Legg, "with a devastating infection sweeping through cassava crops across a vast geographical area." As with HIV/AIDS, control practitioners are playing 'catch-up': worse still, many of the most severely mosaic-affected zones correspond to areas that have suffered most from HIV/AIDS in recent years.

In Mutimbuzi, on the outskirts of Bujumbura, Stany Sabuwanka sustains his family of six on a small half-hectare plot. They depend on cassava for their food security. In a good year, just under half of what he grows is sufficient to feed the family, with the rest being sold to provide a modest cash income. But his cassava is sick. His field - like many others in the fertile zone surrounding Burundi's capital - has been touched by the advancing 'front' of the mosaic pandemic. Stany is still positive. "We really don't know what is causing the crop to change like this, but it's probably the drought. Things should improve when the rains come." But the situation is unlikely to improve. At least not until Stany and other farmers get support through the country's cassava mosaic mitigation effort.

A countrywide initiative

A countrywide management programme for the disease is being led by the Burundi Institute of Agronomic Science (ISABU), with support from IITA, the East Africa Root Crops Research Network (EARRNET) and a number of other partners, including FAO and several NGOs. Although initial progress has been slow (cassava normally takes a year to mature and is propagated through stem cuttings), the pace is increasing as is the commitment to restore Burundi's cassava crop in the quickest time possible.

"The impact of the epidemic in our country has been terrible," says ISABU's Cassava Programme Leader, Simon Bigirimana, "but we have a solution: resistant cassava varieties." Bigirimana refers to the far-reaching potential of elite new mosaic-resistant varieties of cassava recently introduced to Burundi. Resistant varieties, initially developed through IITA's continental breeding programme, have been introduced into Burundi with assistance from EARRNET. Since 2003, the Burundi team have worked, supported by a mitigation grant from USAID's Office for Foreign Disaster Assistance (OFDA), to identify the most mosaic-resistant varieties and multiply these as rapidly as possible. By the end of 2006, tens of millions of life-saving cassava cuttings will have been produced, providing hope for a people that have experienced more than their fair share of hardship in recent years.

A cassava leaf sits proudly at the centre of the flag of CNDD-FDD, the winning party from Burundi's recently concluded elections. As its success brings hope to Burundians for a new era of peace and development, cassava too looks set to play a vital renewing role in the life of this nation.

Article written by James Legg