Global nutrition threatened by climate change-related wheat disease, experts flag

05 Feb 2024 --- A fungal blast disease could reduce global wheat production by 13% before 2050, equating to 60 million tons lost annually, according to a new study. The fungus Magnaporthe oryzae is thriving under conditions created by climate change in tropical regions.

The pathogen is predicted to have devastating effects on human nutrition in parts of South America, Southern Africa and Asia.

“A consequence of losing wheat as a staple food in some of the subtropical regions poses concerns about micronutrient deficiencies in populations heavily dependent on wheat-based diets,” Dr. Senthold Asseng, study lead and professor of digital agriculture at the Technical University of Munich, Germany, tells Nutrition Insight.

“In the context of food insecurity in vulnerable regions, losing wheat due to disease damage exacerbated by climate change would likely impact the nutritional well-being of some of the most vulnerable groups.”

The pathogen is predicted to have devastating effects on human nutrition in parts of South America, Southern Africa and Asia.Crop diversity
Published in Nature, the study was conducted jointly by Dr. Asseng and experts based in Bangladesh, Brazil, Mexico and the US.

According to the findings, up to 75% of the wheat cultivation area in South America and Africa could be at risk in the coming decades. The viral threat could soon significantly affect countries it had only marginally reached until recently, such as Argentina, Bangladesh and Zambia. Regions previously untouched by the fungus are now registering cases, including Uruguay, some south-eastern US states, East Africa, India and Eastern Australia.

The risk to wheat cultures in Europe and East Asia is estimated to be lower, with notable exceptions being the Mediterranean regions of Italy, Southern France, Spain and the humid regions of South-East China.

Urgent action
The paper calls for urgent action to adopt mitigation strategies, including ensuring the resilience of new cultivars, identifying and integrating disease management strategies and equipping farmers with the tools needed to mitigate the upcoming nutrition crisis.

“During crop breeding for disease resistance, nutritional composition of new wheat varieties is always part of the process,” states Asseng.

In Brazil, where blast disease was first spotted in 1985, farmers are already responding to the crisis by replacing wheat with maze.

“Wheat is the most important crop for global calorie and protein supply and is often a higher yielding crop than other unproved crops. However, increasing the diversity of crops for food supply and improving other crops in specific regions for more diversity in food supply could be an important strategy to adapt to the disease threat caused by climate change,” Asseng argues.

Nutritional adequacy
Discussing the nutritional considerations that should be taken into account when substituting crops and the impact this could have on the overall health of communities, he points out that:

“Wheat has a larger range of nutrients than other crops like maize might not have.”

‘Therefore, increasing the diversity of crops for food supply in regional food production by simultaneously considering the nutrients from various crops would be important under future climate change-affected conditions.”

Some of the areas found to be most susceptible to the wheat disease are simultaneously experiencing a rise in wheat consumption by urban populations.

“Discussions on the need to diversify urban diets to ensure nutritional adequacy are happening already, and the potential challenges posed by reduced wheat production add to the urgency in looking for new solutions,” says Asseng.

By Milana Nikolova

This feature is provided by Food Ingredients First’s sister website, Nutrition Insight.

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