Scientists have expressed concern about the “devastating” effects that fungal disease in crops will have on the world’s food supply unless international organizations band together to develop fresh methods of infection control.
Worldwide, growers lose between 10 and 23 percent of their crops to fungal infection each year, despite the widespread use of antifungals. An additional 10-20 percent is lost post-harvest (GS1).
In a commentary in Nature, academics predict those figures will worsen as global warming means fungal infections are steadily moving polewards (GS2) (GS3) (GS4) (VL5), meaning more countries are likely to see a higher prevalence of fungal infections damaging harvests.
Infections of the typically tropical wheat stem rust have already been recorded by growers in Ireland and England. The experts also issue a warning that fungi’s resilience to warmer temperatures may make it more likely for opportunistic soil-dwelling diseases to infect animals or people.
Professor Sarah Gurr, Chair in Food Security at the University of Exeter, co-authored the report. She said fungi had recently attracted attention through popular hit TV show The Last of Us, in which fungi take over human brains.
She said: “While the storyline is science fiction, we are warning that we could see a global health catastrophe caused by the rapid global spread of fungal infections as they develop increasing resistance in a warming world. The imminent threat here is not about ‘zombies,’ but about global starvation.”
Fungal infections are threatening some of our most important crops, from potatoes to grains and bananas. We are already seeing massive losses, and this threatens to become a global catastrophe in light of population growth. Recently, we’ve seen the world unite over the human health threat posed by covid. We now urgently need a globally united approach to tackling fungal infection, with more investment, from governments, philanthropic organizations, and private companies, to build on the seeds of hope and stop this developing into a global catastrophe which will see people starve.Professor Sarah Gurr
Because of expanding populations and increased demand, food security is predicted to face unprecedented challenges worldwide. Infections result in losses that are equivalent to enough food to supply 600 million to 4 billion people with 2,000 calories per day for a year across the five most significant calorie crops: rice, wheat, maize (corn), soya beans, and potatoes.
Commentary co-author Eva Stukenbrock, professor and head of the Environmental Genomics group at Christian-Albrechts University of Kiel, Germany, and fellow of the Canadian Institute for Advanced Research (CIFAR), said:
“As our global population is projected to soar, humanity is facing unprecedented challenges to food production. We’re already seeing massive crop losses to fungal infection, which could sustain millions of people each year. This worrying trend may only worsen as a warming world makes fungal infections more prevalent in European crops, and as they continue to develop resistance to antifungals. This will be catastrophic for developing countries and will have a major impact in the Western world, too.”
The remark highlights a “perfect storm” that is hastening the spread of fungal infections. One of them is the extraordinary adaptability of fungi, which may survive in soil for up to 40 years and have airborne spores that can cross continents. Added to this, they are extremely adaptable, with “phenomenal” genetic diversity between and among species.
The huge expanses of genetically identical crops used in modern farming practices serve as the ideal feeding and breeding grounds for such a prodigious and rapidly evolving group of organisms. They are also well equipped to evolve beyond traditional means to control their spread.
Fungi can develop resistance to certain fungicides, rendering them ineffective, as antifungal treatments that focus on a single fungal cellular activity become more and more common. In an effort to prevent infection, this encourages farmers to use fungicide at ever-higher quantities, which can hasten the emergence of resistance.
However, there is some cause for hope. In 2020, a team the University of Exeter (GS6) discovered a new chemistry which could pave the way for a new type of antifungal targets several different mechanisms, meaning it is much harder for fungi to develop resistance.
The Exeter group found the antifungal to be useful against a range of fungal diseases Septoria tritici blotch on wheat, rice blast, corn smut(GS7), and against the fungus which causes Panama disease of bananas.
After a study in Denmark showed promise by planting seed combinations that carry a variety of genes that are resistant to fungal infection, farming methods may also hold the key to change. With AI, citizen science, and remote sensing technologies like drones enabling early identification and control of outbreaks, technology may also prove vital.
Overall, the authors argue that protecting the world’s crops from fungal disease will require a far more unified approach, bringing together farmers, the agricultural industry, plant breeders, biologists, governments, policymakers, and funders.
Professor Sarah Gurr concluded: “Fungal infections are threatening some of our most important crops, from potatoes to grains and bananas. We are already seeing massive losses, and this threatens to become a global catastrophe in light of population growth. Recently, we’ve seen the world unite over the human health threat posed by covid. We now urgently need a globally united approach to tackling fungal infection, with more investment, from governments, philanthropic organizations, and private companies, to build on the seeds of hope and stop this developing into a global catastrophe which will see people starve.”