Coffee as we know it at risk of dying
A vicious fungal plague wiping out entire coffee plantations is threatening New Zealand's supplies of American coffees.
Outbreaks of coffee rust have swept through Central America in the past two years, destroying the livelihoods of small farmers and drastically cutting the number of beans available for New Zealand.
It could change coffee as we know it forever.
Rene Macaulay, head roaster at People's Coffee, said some of the co-operatives he dealt with had lost 40 to 50 per cent of their crop. In the worst cases, farmers had lost 90 per cent of their plants, with whole plantations reduced to withered, barren sticks.
The only way to treat the disease - known in Spanish as la roya, or the rust, is to uproot the plant and burn it. "Last year at least five countries declared a national state of emergency," Macaulay said. "Latin America has been hit hard."
Four million people in Mexico and the rest of Central America rely on coffee for a living. The most vulnerable are small farmers producing organic beans for high-quality roasts such as those drunk in New Zealand every day.
Rust-resistant strains are being bred from robusta coffee, which is mainly used for instant coffee. But that meant the special types savoured by coffee lovers might be wiped out or become extremely expensive, Macaulay said.
"The price is likely to go up . . . The high-quality coffee, the stuff we drink in cafes, is going to slowly disappear.
"The new [rust-resistant] varietals are high-yield, pest-resistant and weather-resistant, but they aren't bred for their flavour."
Years of low prices have meant the farmers growing the artisan beans could not afford to replace older plants, which are more vulnerable to attack. Because so many of the farmers also depend on organic status, they have not been able to use pesticides and chemicals to try to halt the fungus.
The epidemic has been driven by higher temperatures and humidity in the mountains, encouraging fungal growth - which may be caused by climate change.
Rust is one of the factors driving higher coffee prices globally. The New York Times reported wholesale coffee prices had risen 70 per cent since November, propelled by a drought in Brazil, the world's main producer, and the rust epidemic.
Not all of Wellington's many coffee companies import from affected parts of Central America. Havana Coffee founder Geoff Marsland said his company had been lucky not to have to deal with rust so far.
"La roya is not an issue for us. In the areas we work in it's a threat but nobody I work with has been affected by [coffee rust]."
Caused by the fungus hemileia vastatrix. Infected plants are covered with orange fungal blooms on their leaves, giving a rust-like appearance. Arabica plants are particularly vulnerable.
As a defence mechanism, plants drop their leaves and weaken, produce fewer buds and ultimately die.
Rust outbreaks have been known since the 19th century, beginning in Kenya. When it appeared in Sri Lanka in the 1870s it wiped out coffee there – which is why Sri Lanka is now famous for tea.
Coffee grown worldwide has little genetic diversity, which increases the risk posed by blights such as coffee rust. Higher temperatures and humidity encourage the fungus to grow, and the latest epidemic in Central America may be traced back at least partly to climate change.
Pesticides can be used to control the spread of the fungus, but once it is in a tree little can be done.
There is no treatment other than burning infected plants.
Resistant varieties of plant have been bred, but they tend not to be of the tastiest types of coffee.
The Dominion Post