Coffee scientists from around the world last week flew into Colombia's Eje Cafetero region, a verdant collage of deep gullies and mountainsides covered in thousands of small-scale coffee farms framed by banana trees. At the heart of the 25th International Conference on Coffee Science (ASIC) was a burning question: how to deal with coffee leaf rust, or roya. The world's most damaging coffee disease, leaf rust has torn through Latin America, costing farmers an estimated $1 billion and cutting some harvests by more than half in Central America. Between copious coffee breaks, scientists announced several new molecular techniques to help combat this continental epidemic.
Resistant coffee plants
Helping the coffee plant defend itself from the fungus is a top priority. Colombia leads the world in developing rust-resistant coffee breeds, also known as cultivars. When coffee leaf rust—which was first spotted in East Africa in the 1860s—made it to South America in the 1970s, Colombia's national coffee research center, Cenicafé, was already a decade into its rust resistance breeding program. Since then, it has released two major coffee cultivars—Colombia (in 1980) and Castillo (2005)—that have been effective since 1983 in tempering leaf rust while preserving the characteristics so important to world-class coffee: high yield, large grain size, great taste.