The problem

Starting in the 2011-2012 harvest season, coffee farmers across Central America began noticing an unsettling sight: The leaves of their coffee trees were covered in a powdery orange lesion. It was a fungus called coffee leaf rust. When a plant is badly affected, the infected leaves  drop to the ground, and short-circuit the plant’s ability to generate energy and thus yield a crop. For many farmers, it caused the loss not just one crop cycle but two or more: Meaning no income for multiple years in a row for an already vulnerable population of smallholders. (For more information on the disease, read here.)

Within a year, the epidemic had spread across the region. Five years later, the Central American coffee leaf rust epidemic had devastated the region, affecting 70% of farms. Over 1.7 million coffee workers lost their jobs and it caused $3.2 billion in damage and lost income. Many farmers gave up on farming coffee and will not come back.

Rust wasn’t completely new to farmers in the region. It arrived in the Americas in the 1960s and can be managed under most circumstances, but major epidemics have periodically wiped out major coffee regions. One of the most famous cases is Ceylon (Sri Lanka), which we now associate with tea cultivation. The island used to be planted almost exclusively in coffee. In 1892, a leaf rust epidemic wiped out all of the coffee trees on the island, and farmers switched to tea. In Central America, significant coffee acreage has been lost to rust, ranging up to 50% in some countries.

World Coffee Research in 2013 convened an emergency summit in Guatemala to discuss what could be done at the location, national, regionally, and global levels. One of the key outcomes was the formation of a Global Development Alliance with USAID and other partners to conduct core scientific research that would address the problem of rust. The project is called Revitalizing the Central American, Caribbean and Peruvian Coffee Sectors after the Rust Crisis of 2012 through Applied Research and Development.

Plant diseases thrive based on five factors: Plant genetics (e.g., is the plant resistant to the disease?); management practices (e.g., shade, pruning, and plant nutrition; chemical control (e.g., fungicides and pesticides, including those permissible under organic certifications); the environment; and the disease itself, which can evolve over time—and it has been widely reported that coffee leaf rust may be evolving new races.

The solution

The Central American rust epidemic uncovered dire inefficiencies in dis¬ease monitoring and farm-level resources for coping with disease. World Coffee Research is focusing on applied research around plant genetics and farm management, including the need to provide farmers with better guidance on how to use chemical controls. WCR has initiated multiple applied research projects to address rust through the Global Development Alliance.

Project descriptions for each of the following can be found at the bottom of this page under "related projects":

• Creating next-generation hybrid varieties that are rust-resistant and high quality
  
• Variety Intelligence—publishing a coffee catalog to help farmers understand the differences between coffee varieties and how to manage them
  
• Seed and nursery verification program—helping farmers gain access to healthy, genetically pure varieties, including rust-resistant varieties 
  
• International Multilocation Variety Trial—a platform for global research into the interaction between coffee genetics and environment
• Technical manual for managing coffee leaf rust—producing a manual for agronomists and technicians in Central America, reflecting new knowledge about coffee leaf rust. (project summary coming soon)
•  Too much fruit?—understanding the relationship between how much fruit a coffee plant produces and its susceptibility to rust
  
• Biocontrol of coffee leaf rust—exploring novel approaches to controlling rust by harnessing symbiotic relationships with coffee microorganisms (project summary coming soon)
  
• Shade and fertilization for rust—untangling the complex relationship of coffee leaf rust to shade cover and plant nutrition (coming soon)