A virulent strain of the black stem rust1 parasite that attacks primarily wheat has recently appeared in Iran. This strain was reported for the first time in Uganda in 1999 and then spread to Kenya in 2001, Ethiopia in 2003 and Yemen in 2007, resulting in serious losses for farmers in these countries. The United States sustained major damage in 1974, when 40% of the wheat harvest was destroyed. According to the FAO, “the discovery of the wheat rust fungus in Iran is very troubling, because if it spreads it could quickly compromise wheat production in the at-risk countries”. This analysis is shared by Yvan Sache, a wheat rust specialist at the INRA (France’s National Institute for Agricultural Research), for whom the threat is all the more troublesome since “80% of wheat varieties grown in the world are susceptible to this strain”.
There is therefore a strong risk if this parasite reaches the major grain growing states in the region such as Afghanistan, India, Pakistan, Turkmenistan, Uzbekistan and Kazakhstan, which together account for 20% of global wheat production.
There are solutions, in particular using more resistant varieties of wheat, and some research is already underway , such as that by the International Center for Research in the Dry Areas (ICARDA) and the International Maize and Wheat Improvement Center (CIMMYT) as part of the Global Rust Initiative (GRI) project. However, access to such varieties is often limited for many developing countries.
Without being fatalistic, one thing is sure: the uncertainty related to the spread of wheat stem rust is accompanied by high tension on the wheat market, which will contribute to the already high volatility of wheat prices…even more so since global stocks continue to shrink.
1 Black stem rust, also known as Puccinia graminis, is a parasite that causes pustules to appear on grains and breaks the skin on the plant’s stem.