Coffee Leaf Rust: An Existential Threat?
In 2012 the Royal Botanic Kew Gardens in London released a ground-breaking study that used computer modelling to predict how climate change would impact the future of wild Arabica coffee plants. The bleak findings shared that if trends continue Arabica coffee could be extinct in 70 years. Headlines proclaiming coffee’s possible extinction in 2050 appeared in multiple media channels throughout the world and continues to pick up interest today. Coffee was on the endangered list and the primary cause was climate change. To provide a bit of context, this was also the time when Ethiopian farmers had experienced several poor harvests which were attributed to climate change. Meanwhile, in Central and South America coffee Leaf rust had begun to spread, harming approximately 70% of coffee farms and creating more than 3.2 billion dollars worth of damage.
Coffee plants are succombing to the attack of rust in tens of thousands of tiny coffee farms across Central and South America. More than half of the coffee-growing land in some locations has stopped producing. Rust generated more than $3 billion in losses and forced over 2 million coffee farmers off their land between 2012 and 2017.Sustainability was not a new conversation by any means, but this study acknowledged the urgency for change.
Changing climatic conditions—greater heat, more intense rain, higher continuous humidity—made coffee plantations more friendly hosts for coffee leaf rust. Temperatures in Central America were higher than average in 2012, while rainfall was sporadic and heavy. Together, these events allowed the rust to move faster through its reproductive cycle: infecting a plant’s leaves, producing spores, releasing the spores, and seeking a new plant to infect. The fungus Hemileia Vastatrix causes the rust, which affects the leaves of coffee trees, lowering yields and damaging the trees, sometimes killing trees.
New Coffee Research
Since 2012 the coffee industry has undergone a dramatic transformation. New research has been pushed to the forefront including the development of several research facilities such as World Coffee Research in 2012 and the Coffee Centre at UC Davis, both based in the United States, in 2013. Major players in the industry have become actively engaged in research both through their own initiatives and strategic partnerships. Sustaining the future of coffee has become the common thread as both the coffee industry and academics with an interest in coffee collaborate to develop solutions. Sustainable practices such as regenerative farming, integrated pest management, shade grown coffee, biodiversity and carbon neutral coffee farms have all been widely adopted across a number of farming regions. Arabica, Robusta and wild varietals of coffee are continually being sourced, researched and catalogued. The collaboration and findings over the last decade have been astounding; however it is clear that there is more work to be done.
Coffee leaf rust reaches Hawaii
Coffee leaf rust made the journey across the Pacific Ocean in 2020, putting Hawaiian coffee plantations in jeopardy. The Covid epidemic is thought to have enhanced the susceptibility of these crops by diverting resources away from coffee management. The market conditions that led to the spread of coffee leaf rust in Central and South America in 2011 were comparable to this. According to the Hawaii Department of Agriculture (HDOA), the highly contagious, crop-killing coffee leaf rust disease (CLR) has now been detected on all main Hawaiian islands.
The rust-causing virus Hemileia Vastatrix was discovered on coffee samples on the islands of Kauai and Molokai in July, according to the agency. The HDOA believes rust has been prevalent among some Kauai coffee plants for at least six months, based on lab testing.
The EPA was notified of the likelihood of coffee leaf rust by a Kauai coffee farmer, while the Molokai samples came from feral coffee plants. Plants there may have been affected for at least three months, according to the government.
Despite the state’s tight quarantine precautions for agricultural products, including emergency measures put in place after the discovery of leaf rust on the island of Maui last October, the disease had spread throughout Hawaii by mid-November.
The difference is that Hawaii now has a better grasp of the disease, including its transmission pattern, prevention tactics, and treatment techniques, thanks to considerable research over the last decade. The development of Arabica coffee varietals resistant to coffee leaf rust and other diseases has also been a focus of research.
Since 2012 the coffee industry has undergone a dramatic transformation. New research has been pushed to the forefront including the development of several research facilities such as World Coffee Research in 2012 and the Coffee Centre at UC Davis, both based in the United States, in 2013. Major players in the industry have become actively engaged in research both through their own initiatives and strategic partnerships. Sustaining the future of coffee has become the common thread as both the coffee industry and academics with an interest in coffee collaborate to develop solutions. Sustainable practices such as regenerative farming, integrated pest management, shade grown coffee, biodiversity and carbon neutral coffee farms have all been widely adopted across a number of farming regions. Arabica, Robusta and wild varietals of coffee are continually being sourced, researched and catalogued. The collaboration and findings over the last decade have been astounding; however it is clear that there is more work to be done.
Professor Catherine Aime Purdue Unversity
The Foundation for Food & Agriculture Research has awarded funding to Purdue University Professor of Mycology Catherine Aime to begin early work on sequencing the coffee leaf rust genome and genotyping rust races. As the fungus evolves, resistant cultivars tend to lose their resistance, according to Professor Aime.
“New cultivars are where the focus is right now because that’s a quicker fix, but it won’t be the long-term answer,” Aime said. “We need to get as much information about this pathogen as possible to solve this problem permanently.”
Coffee is still on the endangered list almost ten years after the Kew Gardens research was published, but there is hope. We must continue to embrace and evolve sustainable farming practices in order to mitigate climate change’s effects. However, for the coffee industry’s long-term viability, these techniques must be combined with an ongoing search for and development of new types.
Dr. Alan Davies of Kew Gardens underlined the importance of a two-pronged strategy focusing on mitigation and adaptation at a webinar held by the Canadian Coffee Association. Although mitigation is the most significant factor in lowering greenhouse gas emissions and achieving net zero emissions, there are other factors to consider. Davis emphasizes that a period of adaptation at the production and farm level is still required. Adaptations at the farm level, such as changing the microclimate of the farm, changing the crop, and least popular, relocating people and crop to a more suitable place, are all part of the path to resiliency, according to Davis. During his presentation, Davies underlined that a future dominated by Robust and Arabica will not result in greater long-term sustainability. Farmers should instead try incorporating underused varietals. Coffea Stenophylla, a variety that was recently rediscovered in West Africa, is one varietal with a lot of potential.
