The potential for stem rust to affect the world 's major wheat production regions has been identified in a series of reports . Abdullah Sailan, a coordinator of wheat research at the Authority, explained that wheat rust diseases usually spread from Uganda to Kenya, Ethiopia and then Yemen, before moving on to Asian countries, Australia, and North America. Two studies by the UN Food and Agriculture Organisation ( FAO ) in 2017 found new strains of yellow and black rust had appeared in various parts of the world in 2016 , while older strains spread in Europe , Africa and Asia . Another study , published in Nature Plants in 2017 , confirmed Yemen was at risk of spreading stem rust to these regions . The FAO estimated that 31 north and east African countries and Asia are responsible for 37 % of wheat production worldwide .
The potential for stem rust to affect the world 's major wheat production regions has been identified in a series of reports . Two studies by the UN Food and Agriculture Organisation ( FAO ) in 2017 found new strains of yellow and black rust had appeared in various parts of the world in 2016 , while older strains spread in Europe , Africa and Asia . Another study , published in Nature Plants in 2017 , confirmed Yemen was at risk of spreading stem rust to these regions . The FAO estimated that 31 north and east African countries and Asia are responsible for 37 % of wheat production worldwide .