Species of fungus, driven by trade, travel and climate change, pose a mounting threat to food supplies and biodiversity, scientists warned Wednesday.
Widely unknown to the public, seven fungal epidemics are under way, striking bees, bats, frogs, soft corals and sea turtles as well as rice and wheat, they said.
Human health and livelihoods are at stake, for fungus costs $60 billion a year in losses to corn, wheat and rice alone, according to their assessment, published by the science journal Nature.
“In both animals and plants, an unprecedented number of fungal and fungal-like species have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security,” it warned.
The paper said a lethal skin fungus called Batrachochytrium dendrobatidis, discovered in 1997, has infected 500 species of frogs and toads in 54 countries, on all continents where amphibians are found.
Bats in Canada and the U.S. are being decimated by “white nose syndrome,” a pathogen called Geomyces destructans, which causes a white fungal patch to grow on their muzzles.
Species of the Microsporidia family of fungus are being blamed in part for so-called colony collapse disorder among honeybees.
In tropical climates, the fungus Fusarium solani is causing eggs laid by the loggerhead turtle to fail to hatch, while a soft coral, the sea fan, is in decline, its immune system depressed by a soil fungus.
A pathogen called Magnaporthe oryzae, causing a disease called rice blast, has led to losses of 35 per cent in the rice harvest in 85 countries.
Another fast-emerging concern for farmers is wheat rust, caused by Puccinia graminis. A strain called Ug99 can cause 100-per-cent crop loss, helped by farmers’ over-dependence on a single wheat type.
Fungal destruction of these crops, and also of corn, potatoes and soy-beans, currently amounts to 125 million tonnes a year, the study says. Tackling the problem would be enough to feed one in 12 of the world’s population.
Fungus is spread by tough, virulent and long-living spores that can be borne by wind or water.