Researchers from Aarhus University and the International Maize and Wheat Improvement Center (CIMMYT) are warning that new races of yellow rust and stem rust emerged in 2016 in in different parts of the world. The research was published in a recent issue of Nature.
“These new, aggressive rust races have emerged at the same time that we’re working with international partners to help countries combat the existing ones, so we have to be swift and thorough in the way we approach this,” said Fazil Dusunceli, a plant pathologist at the FAO. “It’s more important than ever that specialists from international institutions and wheat producing countries work together to stop these diseases in their tracks — that involves continuous surveillance, sharing data and building emergency response plans to protect their farmers and those in neighboring countries.”
Wheat rust spreads rapidly and over long distances, carried by wind. Left untreated, rust will devastate healthy looking crops weeks from harvest, leaving the plants with yellow leaves, black stems and shriveled grains. Fungicides may be used to treat infected plants.
Newly identified wheat rust hot spots include:
- In Sicily, TTTTF, a new stem rust race, affected several thousand hectares planted to durum in 2016. The outbreak was the largest in Europe in decades, and the FAO warned that bread wheat may be susceptible to damage from TTTTF.
- A yet-to-be named race of yellow rust emerged in 2016 in Italy, Morocco and four Scandinavian countries. Until recently, yellow rust had scant presence in Morocco and Italy.
- Wheat growers in Ethiopia and Uzbekistan have been combating yellow rust AF2012 outbreaks. The rust significantly cut into Ethiopian wheat production in 2016. Before last year, AF2012 only had been seen in Afghanistan.
“Preliminary assessments are worrisome, but it is still unclear what the full impact of these new races will be on different wheat varieties in the affected regions,” Dusunceli said. “That’s what research institutions across these regions will need to further investigate in the coming months.”
Additionally, already established rust races continued to cause problems. The Warrior yellow rust race, which first appeared on the scene in Turkey and Europe a few years ago, was widely prevalent in Europe and west Asia in 2016. The Digalu (TIFTITF) race of stem rust has continued to wreak havoc in Ethiopia.
“The most well-known race of stem rust — the highly potent Ug99 — is now present in 13 countries,” the FAO said. “Having spread in a northward trend from East Africa to the Middle East, Ug99 has the potential to affect many wheat varieties grown worldwide as it keeps producing new variants. Most recently, it has been detected in Egypt, one of the Middle East’s most important wheat producers.”The FAO is in the midst of a four-year global wheat rust program, which facilitates regional collaboration and offers helps countries boost surveillance capacity.