Climate-driven coffee rust threatens farmer’s futures

By Hannah Booth
Honduras Weekly

Many coffee farmers across Central America will not turn a profit in 2013 and some will even go out of business due largely to the near-epidemic levels of coffee rust disease occurring across the growing regions. “Poor harvests and low market prices this year will deal a lethal blow to many marginal coffee farmers,” said Dr. Tim Schilling, Executive Director of World Coffee Research (WCR) at the Borlaug Institute of International Agriculture at Texas A&M University.

Total production of high-altitude, and thus high-quality, arabica coffee from Central America will be reduced significantly. About 20 percent of all Central American coffee production due to rust and other diseases will be affected in this coffee cycle. The Guatemalan Coffee Board, ANACAFE, estimates that production in Guatemala will be significantly affected due to this year’s rust outbreak. “Due to unusually high rainfalls at high altitude this year, the coffee rust disease has wreaked havoc on arabica coffee yields all across Central America,” Dr. Schilling said.

 Meanwhile, Ric Rhinehart, Executive Director of the Specialty Coffee Association of America (SCAA) says “This is especially worrisome for the U.S. Specialty market that sources its beans from the small, high altitude farms in Central America.”

 Hemileia vastatrix, or coffee rust, causes some damage in any year but can be devastating when conditions are especially favorable for its rapid growth. “This year turns out to be just that… the perfect storm for coffee rust in Central America,” said Dr. Benoit Bertrand, coffee breeder from CIRAD, the French development agency that works with tropical crops.

High rust-spore populations were left on the ground from last year and heavy rainfall allowed rust disease to multiply and rapidly attack coffee plant leaves, reducing physiological activity and thus the plant’s ability to produce. “Those scenarios made this year’s rust attack particularly devastating”, Dr. Bertrand said. “In some cases, coffee bushes have lost all their leaves, branches have withered completely to the extent of sometimes killing off the entire tree.”

Many stakeholders in the coffee sector have wondered whether the severe outbreak of rust this year was due to a virulent ‘mutant’ race. But work by CENICAFE scientists in Colombia proves that theory invalid. “This year’s rust outbreak is not a new strain of the disease, but the same ‘RACE II’ of H. vastatrix commonly associated with rust damage in coffee around the world,” Dr. Bertrand said. “The outbreak can be credited to this year’s high continued rainfall.”

Dr. Schilling says it is likely that, “wild and extreme climate events like this will continue and cause more problems as time goes on.  We simply must invest in research to provide solutions to farmers while governments and the UN try to fix the global climate crisis.”

Most Central American coffee countries have already harvested this year’s crop while others continue to harvest. Farmers, governments and development agencies now pose a question as to how coffee rust disasters like that of Central America can be avoided in the future.

One of the surest short-term protection actions involves the application of a systemic fungicide to the coffee plant before the disease damages the plant.  Dose, timing and frequency depend on local conditions and recommendations. It is important to start the application with the first rains. “Although the application of fungicides can be effective in the short term”, Dr. Bertrand says, “it is nevertheless expensive, laborious, and environmentally unsound”.

 The best way to protect against rust in the medium and longer terms is through the use of a resistant variety of coffee. The good news is that resistant varieties do exist and even some of the new F1 Hybrids from different sources possess rust resistance combined with other desirable agronomic traits. The bad news Dr. Schilling says “is that the resistance to rust of nearly all available varieties is specific for only RACE II of the disease and that the resistant genes come from the robusta coffee species, a lesser quality species than arabica. For the quality coffee market, this is not the best of news”.

Not only are many of these varieties of inferior quality when compared to their arabica parents but, as the resistances come from a genetically very narrow source of robusta, when the disease produces a mutation, the world’s coffee varieties will be susceptible and what happened in 2012-2013 will be far worse with far greater world coffee production repercussions.

World Coffee Research, various national coffee research institutes and others are working toward developing new pre-breeding populations that will possess more than 10 times the level of genetic diversity used to produce today’s coffee varieties.  It is expected that the increased diversity will result in new rust resistance genes with arabica backgrounds and thus high quality.

“We’re confident that the work we’re doing together with the excellent work of the national programs in Colombia, Brazil, Kenya and PROMECAFE will alleviate the problem,” Dr. Schilling said. “WCR is working together right now with these institutions and NGO’s like FTUSA and other stakeholders to organize an emergency conference to figure out what to do to control and prevent rust in the short, medium and long terms in a coordinated and sustainable way.”

Note: The author is with The Texas A&M University System, College Station, Texas.