Coffee Rust (Roya in Spanish) is a fungus (Hemileia vastatrix) that attacks and lives off of coffee leaves until the plant is destroyed. Because of the devastating effects of this fungus on coffee plantations, Coffee Rust has quickly become the most economically important coffee disease in the world. Researchers from the University of Hawaii have traced Coffee Rust back to its roots; it was first reported in 1861 by British explorers in Kenya. It wasn’t until 1970 that the disease had reportedly spread to the western hemisphere when it was discovered in plantations in Brazil.
The fungus presents rust colored lesions on the leaves of more mature plants. The damaged leaves have compromised photosynthetic capacity and coffee cherry size is often drastically reduced in infected plants. Because Arabica plants are most commonly effected by Coffee Rust, this fungus is an extreme detriment to the coffee industry causing devastating annual losses and many small, family operated plantations to shut down. Many scientists are linking extreme weather to the recent eruption of Coffee Rust in places like Guatemala and other Central and Latin American countries. In 2013, Guatemala sold 40% less coffee because of Roya. Only 0.1% of annual coffee revenue is being spent on research and development of technology to combat this coffee killer. New coffee varieties that are rust resistant exist, however they cost nearly four times as much as normal Arabica plants; a luxury in the recently growing coffee crisis. Very few struggling farms would be able to afford these specialized coffee plants.
However there is hope on the horizon, many organizations are putting their efforts into coming up with sustainable practices to help combat the onslaught of the worst coffee menace on record. With the help of organizations like Sustainable Harvest, perhaps we will soon be able to call Coffee Rust a pest of the past.