Forget for a second that global warming will soon render several farming regions that produce much of the world's supply of Arabica coffee untenable as soon as 2020: Costa Rica's coffee plantations are at the moment being devastated by a fungus called "coffee rust." Authorities are saying that the 2013-14 harvest may be halved in the hardest hit farming areas. What's worse is that coffee rust is affecting crops in other countries, and a University of Michigan in Ann Arbor-based ecologist named John Vandermeer tells Nature that the outbreak now includes “reports of devastation in Nicaragua, El Salvador and Mexico."
Coffee rust, or Hemileia vastatrix, which covers leaves in orange and/or yellowish powdery spots, is actually common on coffee plantations. The powder literally overshadows and burdens coffee leaves to the point that cells can no longer function, and while the fungus is usually kept under control with sprays, authorities in Costa Rica are considering the scope of the current outbreak so severe that last week the government enacted emergency legislation to divert government funds to try to salvage the harvest. Outside of the country, Vandermeer says coffee rust is affecting the coffee plants at his research station in Mexico to the extent that 80 percent have been losing their leaves, and 30 percent have no leaves at all.
The fungus was first identified in 1861. It destroyed more than 90 percent of the coffee crops in Ceylon at the time and continued to be an issue thereafter in the East, but coffee rust only made its debut in the Western hemisphere when it popped up in Brazil in 1970. It is thought to have stowed away with some cacao and coffee seedlings from Africa. Since then, severe outbreaks in Central America, South America, and Africa have been kept under control with fungicides, but scientists are now warning that cross-breeding resistant varieties of coffee plants may be the only way to stave off widespread crop devastation. If an intervention is not effective, they warn, the dramatically decreased output could lead to shortages, or even economic crises.