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A rapid increase in fungal attacks on crops – exacerbated by climate collapse – could become a “catastrophe” for the world’s food supply, scientists have warned.
Already the single most important threat to crops worldwide, fungal infections are estimated to destroy 10 to 23 percent of farmers’ annual production, plus an additional 10 to 20 percent after harvest by spoiling enough wheat, rice, corn, potatoes and soybeans to feed up to 4 billion people with 2,000 calories a day for a year.
But in an article published in the leading magazine Naturescientists have warned that the ‘perfect storm’ of food production techniques that fueled the current situation could be further intensified by rising temperatures.
Global warming means that plant pathogens, including fungi, previously confined to southern regions are now spreading towards the north pole, with fungal infections estimated to be moving north at a rate of around 7 kilometers per year from 90’s.
In one such example, farmers have already reported wheat stem rust infections, which typically occur in the tropics, in Ireland and England.
Scientists have warned that rising temperatures could also cause fungi that already live harmlessly in plants in colder countries to become pathogenic and could make soil-dwelling pathogens more capable of leaping off plants to infect warmer hosts. , such as animals and humans.
Fungal pathogens are thought to claim at least 1.5 million lives each year, close to the number killed by malaria and tuberculosis, prompting the World Health Organization to warn in October that they are becoming “increasingly common and resistant to treatment”.
While the United Nations health agency has cited the climate crisis and human trade and travel as driving the rise in human infections, the new study indicates that agricultural practices provide “perfect” conditions for fungi to infect crops.
Describing the threat to plants as “another major threat to human health” – alongside one that fungi directly pose to humans, particularly among those with weakened immune systems – the authors warn that a united global action to address the problem.
‘Fungal infections are threatening some of our most important crops, from potatoes to cereals and bananas,’ said co-author Professor Sarah Gurr, from the University of Exeter. “We are already seeing huge losses and this threatens to become a global catastrophe in light of population growth.
“Recently, we have seen the world unite over the threat to human health posed by Covid. We now urgently need a united global approach to tackling fungal infection, with increased investment, from governments, philanthropic organizations and private companies, to build on the seeds of hope and prevent it from turning into a global catastrophe that will see people die of hunger”.
The fungi are incredibly resilient, and spores of some species can remain viable in soil for up to 40 years, while airborne spores of other species, such as wheat stem rust, can travel between continents, according to the authors.
They are also said to be extremely adaptable, with “phenomenal” genetic diversity between and between species.
Modern agricultural practices, in which genetically uniform crops are grown over large areas, ‘provide ideal nutrition and breeding grounds for such a prolific and rapidly evolving group of organisms,’ warns the paper.
Furthermore, the increasingly widespread use of antifungal treatments that target only a single cellular process in fungi has led to the emergence of fungicide resistance, say the authors.
While the authors – prof. Gurr and Professor Eva Stukenbrock, of the German University of Kiel – warn of the possibility of a “catastrophe”, they also say that there is reason to hope.
They point to new research in Exeter that could pave the way for more complex antifungal treatments much less likely to fuel fungicide resistance, and a Danish study with promising results in which farmers planted seed mixes containing a range of fungicide-resistant genes. mushrooms.
Technology may also prove crucial, with artificial intelligence, citizen science and remote sensing tools such as drones enabling early detection and control of outbreaks, said the authors, who called for more investment in fungal crop research .
“Addressing the greatest threats to food security – and therefore to human health – must include addressing the devastating impacts fungi are and will continue to have on the world’s food supply,” they wrote.
