A Call to Action Against the Threat of a Stem Rust Pandemic in Wheat

A group of international wheat scientists met at Washington, D.C. in April to brief officials of the US Agency for International Development (AID) on the imminent threat of a stem rust pandemic in wheat and on the steps needed to contain it.

Their action was prompted by the emergence in Africa of a highly virulent race, named Ug99, of the fungal pathogen responsible for this major disease. Ug99, as its name indicates, was first identified in Uganda during 1999. In experimental wheat plots, the new race of stem rust was shown to reduce grain yields by as much as 71 percent.

By 2005, according to a report from the International Maize and Wheat Improvement Center (CIMMYT), all wheat farms in Kenya, Uganda, and Ethiopia were affected by the new strain, and small farmers in Kenya, who produce 20 percent of the country's wheat, had lost as much as half of their harvest to the disease. CIMMYT scientists predict that in Africa alone wheat yield losses from the disease could approach US$1 billion in value, pushing up the global price of this staple grain and possibly leading to food shortages.

Mobilizing International Science

The delegation that visited USAID headquarters recently was led by Nobel Prize laureate Norman E. Borlaug. Stressing the need to mobilize the international scientific community, he said, "The prospect of a stem-rust epidemic in wheat in Africa, Asia, and the Americas is real and must be stopped before it causes untold damage and human suffering."

Borlaug and other researchers fear that the massive outbreak of stem rust now under way in Africa could quickly lead to a global epidemic. Spores of Ug99, unlike previously known races of the pathogen, can be carried by wind for thousands of miles. Studies have shown that by this means the spores can travel from Africa to parts of the Middle East and even as far as the Caribbean.

In a prior step to organize effective and coordinated action against the threat, CIMMYT and the International Center for Agricultural Research in the Dry Areas (ICARDA) launched the Global Rust Initiative (GRI) at an international summit held during September 2005 in Nairobi, Kenya. The event was organized in close collaboration with the Kenyan Agricultural Research Institute (KARI) and the Ethiopian Agricultural Research Organization (EARO). The GRI is a multidisciplinary research and development consortium, which will rapidly develop and deploy appropriate wheat varieties possessing stable resistance to the new race of stem rust.

A Disease to be Reckoned With

During the first half of the 20 th century, stem rust caused huge wheat losses and even famine. In the 1950s Borlaug embarked on a successful program sponsored by the Rockefeller Foundation in Mexico to combat the disease. Borlaug's innovative work on wheat improvement led to the establishment of CIMMYT. As director of the Center's Wheat Program, Borlaug is credited with being the chief architect of the Green Revolution, which led to widespread adoption of high-yielding, disease-resistant varieties of wheat and rice in developing countries.

The world's second most important cereal crop, wheat is a major source of energy in the human diet . In the developing world, 29 percent of people's daily caloric dietary intake comes from the crop.

For several decades wheat stem rust was held in check through a combination of modern plant breeding and chemical controls. But now in Eastern Africa, the genetic resistance that endured for decades has been overcome by Ug99.

Success in warding off a new global epidemic of wheat stem rust will require concerted action by scientists but also strong support from government decision makers. Effective communication and advocacy will also be critical for ensuring that the public understands the economic, environmental and political risks of wheat stem rust and its consequences for global food security.

Brief Powerpoint Presentation on Wheat Stem Rust

Useful Links

Global Rust Initiative (GRI)
International Maize and Wheat Improvement Center (CIMMYT)
Ethiopian Agriculture Research Institute (EARO)
Center for Agricultural Research in the Dry Areas (ICARDA)
Kenyan Agriculture Research Institute (KARI)
United States Agency for International Development (USAID)