A tenacious fungus is threatening the global coffee supply. Can genetics save our morning cup?
A World Without Coffee?
If you’re drinking a good cup of coffee as you read this, take a moment to savor it. Hug the cup, if you’re so inclined. After all, coffee may not always be so easy to come by.
Coffee rust is a significant problem in almost every coffee growing region in the world, and in recent years, countries in Central and South America have been hit particularly hard. One of these is Colombia, which cultivates around one million hectares of coffee plants to produce more than 65,000 tons of coffee each year. Consequently, Colombia is one of the biggest coffee producers in the world.
Colombia’s primary coffee crop is the highly valued Coffea arabica. Indeed, Arabica beans are the most popular and widely consumed type of coffee in the world. The combined global production of Arabica accounts for around 70% of the world’s coffee.
Unfortunately, it’s not just coffee drinkers who like it. A particular species of Coffee Leaf Rust (CLR) also has an affinity for C. arabica, and with devastating effect.

Coffee producer Adrian Hernandez looks at a plant infested with the coffee-eating fungus roya, at his farm Altamira, in Barva Heredia, Heredia, 17 km north of San Jose, on August 25, 2015. Hernandez does not remember a year as dry as this one and says that only a rigorous management plan has allowed him to stay afloat. Coffee growers in Central America are having to adapt to global warming, including high temperatures and drought, as well as fighting the fungus known as roya, in order to keep in the business. The fungus, hemileia vastatrix, which began to spread in 2012 due to a lack of preventive measures and the effects of climate change, discolors and dries up coffee leaves, an effect that also gives roya the name of ‘leaf rust.’ AFP PHOTO / EZEQUIEL BECERRA (Photo credit should read EZEQUIEL BECERRA/AFP/Getty Images)
They are notorious plant pathogens that disrupt the growth and reproduction of healthy plants. The airborne spores make infection hard to control. Once rust has entered a region, it’s incredibly hard to get rid of.
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