Fungal Attacks Threaten Global Food Supply, Say Experts

An anonymous reader quotes a report from The Guardian: Fast-rising fungal attacks on the world’s most important crops threaten the planet’s future food supply, scientists have said, warning that failing to tackle fungal pathogens could lead to a “global health catastrophe.” Fungi are already by far the biggest destroyer of crops. They are highly resilient, travel long distances on the wind and can feast on large fields of a single crop. They are also extremely adaptable and many have developed resistance to common fungicides. The impact of fungal disease is expected to worsen, the researchers say, as the climate crisis results in temperatures rising and fungal infections moving steadily polewards. Since the 1990s, fungal pathogens have been moving to higher latitudes at a rate of about 7km a year. Wheat stem rust infections, normally found in the tropics, have already been reported in England and Ireland. Higher temperatures also drive the emergence of new variants of the fungal pathogens, while more extreme storms can spread their spores further afield, the scientists say.

The scientists said there was also a risk that global heating would increase the heat tolerance of fungi, raising the possibility of them hopping hosts to infect warm-blooded animals and humans. The warning, issued in an article in the scientific journal Nature, said growers already lost between 10% and 23% of their crops to fungal disease. Across the five most important crops — rice, wheat, maize, soya beans and potatoes — infections cause annual losses that could feed hundreds of millions of people. Fungi made up the top six in a recent list of pests and pathogens with the biggest impact. Fungi are incredibly resilient, the researchers say, remaining viable in soil for up to 40 years, and their airborne spores can travel between continents.

Fungicides are widely used but the pathogens are well equipped to rapidly evolve resistance to treatments that target only a single cellular process. Existing fungicides and conventional breeding for disease resistance are no longer enough, the researchers say. One solution is planting seed mixtures that carry a range of genes that are resistant to fungal infection, rather than monocultures of a single strain. In 2022, about a quarter of wheat in Denmark was grown in this way. Technology may also help, the scientists say, with drones and artificial intelligence allowing earlier detection and control of outbreaks. New pesticides are being developed, with a team at the University of Exeter recently discovering compounds that could lead to chemicals that target several biological processes within the fungi, making resistance much harder to develop. The approach has already been shown to be useful against fungi infecting wheat, rice, corn and bananas. “While that storyline is science fiction, we are warning that we could see a global health catastrophe caused by the rapid global spread of fungal infections,” said Sarah Gurr, professor at the University of Exeter and co-author of the report. “The imminent threat here is not about zombies, but about global starvation.”