Coffee Leaf Rust in Jamaica

Coffee leaf rust, a fungal disease that defoliates and can kill coffee trees, hit Jamaica hard during a regional epidemic that began in 2012. The disease attacks Typica, the variety behind Blue Mountain coffee, more readily than many other varieties, and Jamaican growers now manage it mainly through fungicide, pruning and a long-running effort to breed resistant plants.

The 2012–13 regional coffee leaf rust outbreak

Coffee leaf rust, caused by the fungus Hemileia vastatrix, spread across Latin America and the Caribbean beginning in 2012. USAID estimated the epidemic caused about $1 billion in damage and affected more than 2 million people across the region between 2012 and 2014, and that it cut Central America's coffee output by around 16%. Honduras was especially hard hit: about 80,000 hectares of coffee were infected, roughly 30,000 farmers lost more than half their crop, and about 10,000 lost their harvest entirely.

How coffee leaf rust affected Jamaica

Jamaica's coffee industry felt the outbreak too, without the catastrophic losses reported in parts of Central America. Senator Norman Grant, chief executive of the Mavis Bank Coffee Factory, told the Jamaica Information Service in 2014 that the disease had cost the industry an estimated US$10 million in revenue over the previous three years, and that global coffee production had fallen by about 20% because of it. Jamaica's own Blue Mountain coffee production dropped from about 211,000 boxes a year to about 160,000 boxes, Grant said, describing coffee leaf rust as more damaging than the coffee berry borer, the other pest troubling farmers at the time. "It attacks the trees; the leaves fall off and the tree will die, and you are missing two to three years of production," Grant said.

Why Typica is especially vulnerable

Jamaica Blue Mountain coffee is grown almost entirely from the Typica variety, and Typica is unusually susceptible to coffee leaf rust. World Coffee Research, a nonprofit that tracks Arabica varieties, classifies Typica's rust resistance as low. Part of the reason is historical: nearly all Typica grown worldwide today descends from a small number of seeds carried out of Ethiopia, by way of Java, centuries ago, leaving the variety with very little of the genetic diversity that lets some coffee populations resist disease. The same narrow genetic base also leaves Typica susceptible to coffee berry disease and nematodes, which is part of why many coffee-growing countries have gradually replaced it with hardier varieties, even as Jamaica has kept it central to Blue Mountain coffee's identity.

How coffee leaf rust is managed

There is no single fix once the disease is established. Growers generally rely on copper-based fungicides, such as Bordeaux mixture, applied before infection, and systemic fungicides once rust appears, combined with pruning to improve airflow through the canopy, removing badly infected leaves, and keeping trees well fed with balanced nitrogen and potassium. In Jamaica, the Ministry of Agriculture and Fisheries partnered with Mavis Bank Coffee Factory in 2014 to get inputs to affected growers: Mavis Bank had already put about $20 million into supporting farmers, and the ministry planned to add a further $5 million in fertilizer for growers in Portland, St Thomas and St Andrew, the parishes at the center of the Blue Mountain growing area.

Breeding rust-resistant coffee in Jamaica

Jamaica has also invested in a longer-term response: breeding coffee that resists the disease outright. The Scientific Research Council has worked with the International Center for Environmental and Nuclear Science and the International Atomic Energy Agency on a four-year project that uses irradiation to speed up the natural mutation process that would otherwise take 50 to 60 years to produce new, rust-resistant plant material. As of mid-2022, partway through the project, some affected fields were losing up to 50% of their crop to the disease, and any new plant material would need to meet Jamaica's existing quality standards before release to growers, according to Dr Charah Watson, the council's executive director.

What this means for Blue Mountain coffee buyers

An outbreak year does not necessarily mean lower quality reaches the shelf. Jamaica's grading and certification rules still apply to whatever coffee makes it to export, so beans sold as Jamaica Blue Mountain still have to clear the same bar. What a bad rust year mainly changes is volume and, in turn, price: fewer cherries reach export grade, farmers have less to sell, and a tight harvest can ripple through to what is available internationally the following season.

Rust itself is easy to recognize on the farm, even if treating it is not: infected leaves develop powdery orange-yellow spots on their undersides, and heavily infected leaves eventually drop, thinning the canopy that the tree needs to keep producing.