Fungus poses threat to your morning coffee

For nearly six years, a fungus that’s commonly known as rust has killed so many coffee trees in Central America that scientists have speculated the region could lose up to 40 per cent of its coffee crop.

Now, as researchers scurry to maintain the global coffee supply, there are signs that climate change and wild weather could worsen the problem. “We just keep getting report after report at our partner institutions in those countries - these are growers, buyers, importers and roasters,” says Tim Schilling, director of World Coffee Research at Texas A&M University, describing the problem in places like Panama and El Salvador.

Known as roya in Spanish, the rust fungus has also engulfed parts of Guatemala, Nicaragua, Mexico, Costa Rica and Honduras. The culprit is a phenomenon that scientists call climate variation, which sees weather patterns changing dramatically from year to year. More rain in recent years has meant more rust, which blankets the leaves of coffee trees, cuts off sunlight, and restricts photosynthesis until a coffee tree keels over and dies.

Last year, a United Nations panel of climate scientists found that downpours related to El Niño and La Niña weather events - periodic changes in the Pacific Ocean’s temperature that influence rainfall near the Equator - will intensify this century, leading to even more precipitation.

The problem has attracted attention from Central American governments, which see depressed coffee futures as a threat to their economies. Some coffee producers, meanwhile, have accepted help from development organizations, which fear that too many unemployed farmers could lead to widespread poverty and fuel other problems, like the drug trade.

The United States - which consumes more coffee than any other country, but produces close to zero - recently announced a $5 million grant to Texas A&M’s coffee research program to help combat rust.

The problem of rust is not new in Central America. The fungus has appeared in multiple waves since the 1970s but mutates each time, complicating researchers’ efforts to combat it.

When rust struck Colombia in 2008, it spread from farm to farm, cutting the country’s coffee output from 12 million bags to 7 million in a single year. The country’s economy sputtered. Some farmers - many with less than a single hectare of land - had no crop at all.

The fungus continues to mutate, appearing in Guatemala and Nicaragua in different strains than the one detected in Colombia. Most farmers douse plants in expensive fungicides, but there’s little research on whether chemical treatments work on new strains of rust. The solution, agriculture experts say, is to engineer new plants designed to withstand the attack of the fungus.

“The main strategy is to use genetics,” says coffee researcher Schilling.  His team is working to create rust-resistant seeds with hopes of replacing as many plants as possible in Central America that are susceptible to the fungus.

The biggest question may be whether farmers can be persuaded to let foreign scientists with genetically modified seeds swoop in to replant coffee fields.Governments will likely need to subsidize the seeds.

And nonprofits will have to ensure that those seeds are planted correctly. Many experts wonder if the process, unfolding over many seasons - some years without any yield at all - will drive farmers to try to find other work.