ANN ARBORA shift away from traditional coffee-growing techniques may be increasing the severity of an outbreak of 'coffee rust' fungus that has swept through plantations in Central America and Mexico, according to a University of Michigan ecologist who studies the disease.
The current outbreak of coffee rust is the worst seen in Central America and Mexico since the fungal disease arrived in the region more than 40 years ago. Guatemala recently joined Honduras and Costa Rica in declaring national emergencies over the disease.
The Guatemalan president said the outbreak could cut coffee production by 40 percent in his country for the 2013-2014 growing season. Because Central America supplies 14 percent of the world's coffee, the outbreak could drive up the price of a cup of coffee.
U-M ecologist John Vandermeer has operated research plots at an organic coffee plantation in southern Chiapas, Mexico, for about 15 years. Vandermeer and colleague Ivette Perfecto of the U-M School of Natural Resources and Environment study the complex web of interactions between resident organisms there, including various insects, fungi, birds and bats.
Vandermeer said more than 60 percent of the trees on his study plots now have at least 80 percent defoliation due to coffee rust, which attacks leaves and interferes with their ability to photosynthesize. Thirty percent of the trees have no leaves at all, and nearly 10 percent have died.
"I have personal reports from friends who work in coffee in Colombia, Costa Rica, El Salvador, Guatemala, Nicaragua and Mexico. They all say that it's the worst explosion of this disease they've ever seen," said Vandermeer, a professor in the Department of Ecology and Evolutionary Biology and at SNRE.
Over the last 20 to 25 years, many Latin American coffee farmers have abandoned traditional shade-growing techniques, in which the plants are grown beneath a diverse canopy of trees. In an effort to inc
|Contact: Jim Erickson|
University of Michigan