THREAT TO GLOBAL AGRICULTURE
In the Wheat Fields of Kenya, a Budding Epidemic
Wednesday, February 18, 2009
GREAT RIFT VALLEY, Kenya -- A virulent new version of a deadly fungus is ravaging wheat in Kenya's most fertile fields and spreading beyond Africa to threaten one of the world's principal food crops, according to the United Nations' Food and Agriculture Organization.
Stem rust, a killer that farmers thought they had defeated 50 years ago, surfaced here in 1999, jumped the Red Sea to Yemen in 2006 and turned up in Iran last year. Crop scientists say they are powerless to stop its spread and increasingly frustrated in their efforts to find resistant plants.
Nobel Peace laureate Norman Borlaug, the world's leading authority on the disease, said that once established, stem rust can explode to crisis proportions within a year under certain weather conditions.
"This is a dangerous problem because a good share of the world's area sown to wheat is susceptible to it," Borlaug said. "It has immense destructive potential."
Coming on the heels of grain scarcity and food riots last year, the budding epidemic exposes the fragility of the food supply in poor countries. It is also a reminder of how vulnerable the ever-growing global population is to the pathogens that inevitably surface somewhere on the planet.
The first hint of danger came in an e-mail in 1999 to Ravi Singh, a wheat expert at the International Maize and Wheat Improvement Center in Mexico.
A scientist who had trained under Singh was reporting findings from field trials in Uganda. Singh said he could not believe what he saw: Plants that were bred to resist stem rust had succumbed to the fungal parasite.
"It was shocking," Singh said. "We had never seen such susceptibility. . . . The first thing you think is that it probably is not true."
Researchers in South Africa and Minnesota discovered why it was true. In the biological churning that constantly endows old pests with new genetic combinations, stem rust had acquired a frightening ability to punch through the resistance that had guarded wheat for decades.
Eighty percent of Asian and African wheat varieties are now susceptible, and so is barley, FAO experts said. Scientists named the new menace Ug99 for its discovery in Uganda in 1999. But they say it probably started earlier in Kenya, where more wheat is grown.
The research center in Mexico published a warning of "a pending disaster in global agriculture."
Last March, the FAO confirmed that the fungus had spread to Iran and said in a news release that "Afghanistan, India, Pakistan, Turkmenistan, Uzbekistan and Kazakhstan, all major wheat producers, are most threatened by the fungus and should be on high alert."