Nature: The Wheat Stalker
Njoro, Kenya (Jun 30, 2011) — David Cheruiyot noticed that his wheat fields were turning the wrong colour. The stems of the plants took on a sickly brown hue, and when he peeled open the heads there was no grain inside. “If you go to inspect it, there is nothing but dust,” he recalls.
Ug99, a virulent fungus that causes a disease called stem rust, arrived on Cheruiyot’s farm in Kenya in 2007. It devastated wheat fields in the country that season, slashing yields by as much as 80% in some regions. Since that epidemic, Cheruiyot has sprayed his wheat three times a season with fungicide, something that few farmers in Africa can afford.
Stem rust has plagued farmers for millennia, but Ug99 is a new superstrain that overcomes defensive genes in 90% of the wheat crops planted around the globe. Since it was first detected in 1998, spores of the fungus have spread from East Africa into Yemen and Iran. If the disease continues its march eastwards, hitting the breadbaskets of south Asia and China, it will threaten the food supply of hundreds of millions of people.