A devastating disease is threatening to destroy the coffee industry in South America, according to officials who have warned of the mutation of the devastating fungus.
The coffee rust or coffee leaf rust disease is an orange-powdery fungus, responsible for the demise of Sri Lanka’s (then known as Ceylon) coffee industry in the late 1800s, according to NPR.
“This is one of those rusts that even though it’s been with us for over 100 years, we don’t even understand its entire life cycle,’ Purdue mycologist Cathie Aime, explained.
Across Central America, 70% of Arabica plant farms have been hit by the disease, resulting in $3.2 billion in damage and 1.7 million lost jobs. The Colombian Federation of Coffee Growers has predicted losses of up to 80 percent.
“This is much more difficult than it sounds. For rust fungi, they’re obligate pathogens, so you can’t get pure DNA in meaningful quantities. You can’t grow it in culture or manipulate it in the lab. And they’re microfungi, so you are dealing with extremely small organisms embedded in their host,” the scientist added.
Coffee rust currently has no cure, but can be restricted with preventative application of anti-fungal sprays. Planting crops in higher, cooler altitudes - which range from about 1,800 to 2,100 meters - creates difficulty for fungus reproduction.
Resistant strains Robusta coffee have been developed, but the quality of the beans are inferior to the now-vulnerable Arabica plant. The Lempira strain is popular in Honduras and was resistant until it became vulnerable to the disease in 2017.
The fungus is evolving and will likely become resistant "in five years, in one year, in 10 years," Benoît Bertrand, a coffee geneticist at a French agricultural research organization, said. "We know it is a question of time."
The symptoms of coffee rust include small, yellowish, oily spots that appear on the upper surface of plant leaves which then expand into larger round spots that turn bright orange to red, then brown with a yellow border outline. The disease was first discovered in the Western Hemisphere in the 1970s, in Brazil.
“We are in the middle of the biggest coffee crisis of our time,” one Guatemalan producer and exporter, Josue Morales, said.
Coffee rust has plagued regions of Africa, the Near East, India, Asia and Australasia in addition to destroying the coffee industries in Sri Lanka and Java in the late 1800s.
Coffee is one of the world’s most traded commodities, second only to oil, aided by about half a trillion cups consumed annually.
According to a 2017 study, “coffee-suitable areas will be reduced by 73–88% by 2050 across warming scenarios, a decline 46–76% greater than estimated by global assessments.”