Climate change is encouraging the emergence of new races of rust that are overcoming currently resistant wheat varieties
Wheat rust diseases are well known in the world’s developing countries. Countries have successfully managed rusts over the past decades using disease-resistant wheat varieties. Today the situation and the threat from wheat rust is fundamentally different from the past. Changes in temperature and rainfall patterns have encouraged the emergence of new races of rust that overcome the currently resistant wheat varieties.
Low-income countries need to put in place strategies now for immediate action, medium-term protection and long-term research efforts to develop new wheat varieties that resist the changing rust diseases.
Across the globe, pressures on food security are being made worse by crop diseases that are emerging more frequently and then rapidly spreading. It’s a situation fuelled by climate change and certain farming practices in increasingly fragile ecosystems.
Wheat is one of the most critically important staple foods worldwide. Its harvests have come under increasing threat in recent years from new kinds of fungus infections, such as wheat rusts, that are killing these crops. Wheat rust is well known to farmers and agricultural planners around the world, who have been dealing with it since the early 1900s. But in the past decade, new races have emerged that are overcoming the wheat crops that were previously resistant.
A global problem that hits hardest in low-income countries
Wheat rust is a global problem. But perhaps the greatest threat lies in the broad arc from North Africa through to South Asia – from Morocco to India. Any serious crop disease outbreak or epidemic in these wheat-dependent countries could cost billions of dollars in attempted control and lost agricultural output. The resulting spike in food prices would push bread and other basic wheat-based goods out of the reach of many, with potential political implications.
One of the most critical of these wheat rust diseases is stripe rust. It is spreading more rapidly than in the past and new variations of the disease are overcoming presently rust-resistant wheat varieties that have been developed by researchers in recent years.
The most rapid spread of wheat stripe rust we have ever seen?
Plant pathology experts at the International Wheat Stripe Rust Symposium in Aleppo and elsewhere say that the world may be witnessing – in these rusts – the most rapid spread of important crop disease ever seen. Under the right conditions wheat stripe rust infection can spread – carried by the wind – from one wheat growing region to another in just 24 hours.
Today, the possibility of a serious stripe rust pandemic that devastates millions of hectares of wheat production is more than a ‘scenario’. The disease is widespread and dispersed in almost all wheat growing regions and it presents an uncertain, and changing genetic target for crop researchers and agricultural planners.
Climate change is driving the speed and frequency of today’s new wheat rust problems. It provides the ideal conditions for these new rust races to spread, unchecked, across many countries.
Countries can benefit from each others’ experience in preparedness and rapid response to wheat rust diseases. Those with a more developed framework in place to deal with wheat rusts are able to reduce its negative impact on crop production.