Wheat crops around the world are threatened by a virulent strain of black stem rust fungus (Puccinia graminis), discovered in Uganda in 1999. Ug99 has evolved to take advantage of rust-resistant wheat varieties, and almost no wheat crops anywhere are immune to it. In January this year spores blew across to Yemen, and north into Sudan . Scientists predict it will now blow into Egypt, Turkey and the Middle East, and on to India, lands where a billion people depend on wheat.
The last major rust outbreak in North America, in 1954, wiped out 40 per cent of the crop. During the cold war both the US and the Soviet Union stockpiled stem rust spores as a biological weapon. From the work to counter the outbreak with resistant varieties grew the International Maize and Wheat Improvement Center, CIMMYT. After 40 years with no outbreaks, complacency and lack of funding are blamed for rust’s reappearance.
The first line of defence is fungicide, but poor farmers can’t afford it, or don’t have the equipment or know-how to apply it. Given the potentially global scale of the next rust epidemic, even rich countries will face problems sourcing enough fungicide to fight both wheat rust and other fungal crop infections.
Be prepared for the appearance of rust-resistant GM wheat varieties incorporating genes from other cereals, such as rice, that have never suffered from rust. In the face of world-wide starvation, NGOs such as FoE and Greenpeace may well find it hard to justify their traditional, knee-jerk opposition to GM crops.
But look on the bright side. We can always use the rust-afflicted wheat to make ethanol.