The disease was thought to have died out during the 1960s when the first resistant varieties of wheat were developed. The new strain, known as Ug99 after it was first discovered in Uganda in 1999, releases millions of spores into the air, where they can be carried hundreds of kilometres by the wind, and eventually covers entire plants in a red-coloured fungus. Since its discovery, Ug99 has been detected in Ethiopia, Sudan, Yemen, Iran and Kenya, where it’s believed to have killed off 80 per cent of wheat in some areas.

But following a special meeting attended by hundreds of crop experts in Ciudad Obregón, Mexico, there is hope. According to Dr Ravi Prakash Singh of the International Maize and Wheat Improvement Center, more than 60 new wheat strains have been developed since 2006, each of which contains genes that can resist Ug99 and produce a crop yield that is between five and 15 per cent higher than susceptible varieties.

Crop specialists are working to increase seed stocks of the resistant varieties and are calling on farmers to replace existing varieties before it’s too late. ‘Stem rust disease is known historically to cause famine, so growing susceptible varieties is a major cause for concern,’ said Singh. ‘Farmers in the migration path of Ug99 should seek resistant varieties of seed and grow them in their fi elds before the disease arrives.’

June 2009