When Espresso Blends and Mildew Meet

What you see in this picture is the leaf of Caffea canephora, a coffee plant (known for its "robusta" beans), small specks of moss, and a white powdery layer of mildew. I took this picture in May 2024, in Panama, on a remote farm, covered by rainforest and pastures for cattle. The coffe was planted in 2022, funded by an NGO, to help establish a more sustainable alternative to cattle farming. A small patch of forest was cleared to make space for the coffee, and native vegetation is now cut back regularly to make sure it doesn't overgrow the coffee plants.

This picture is my starting point to better understand the state of the ecosystem and to gather information, before we start spinning up possible pathways to reestablish a native environment. With your help, in future posts the sociological and economic aspect of the ecosystem will be explored. 

Back to the leaf. Powdery mildew, in this case, from the order of Erysiphales, is thought to have migrated from China into the Americas across the Bearing Strait. This order of fungi is known to infect a large variety of plants (cabbage, broccoli, etc.), where each host plant coevolves with a unique fungal species.

The species of Erysiphales on this picture is unknown to me. Mildews are not as harmful to coffee plantations as e.g., coffee rust infections, and hence almost all studies on fungal coffee infections focus on the latter. Let me know if you have a lead or a suggestion on which species it could be. 

While Mildew originated in Asia, Caffea canephora originated in Western Africa (likely Guinea). It is well adapted to hot and humid environments and is now cultivated throughout the tropics.

In many ways this photograph captures a unique encounter. Worlds colliding. It provides us with a precious opportunity to learn about the microclimate on this slope in the rainforest near Jaqué. By studying under what conditions Erysiphales and Caffea canephora occur in their native range, we can use both species and their connection as a bioindicator.

By tracking and understanding how their connection evolves we can track how the microclimate around these coffee plants is changing and evolving.

Already, changes in "behaviour" have been reported. Just recently scientists discovered that Erysiphales species in Panama skip developmental stages, reproducing asexually, while Erysiphales are known to reproduce sexually in temperate zones. What could that mean for the coffee patch near Jaqué?

What are potential implications of Erysiphales in this ecosystem and how would you approach its management? In addition, how would you inform the farmers of an upcoming shortage in coffee beans due to the mildew infestation and how could they balance the losses to make ecologically and financially sustainable decisions moving forward?

Excited for your ideas and thoughts in the comments or in the Ecosystem Clinic Chat. 

Coming Up:

Soil samples from the coffee plantation and the cattle pastures, to analyse the ecosystems current foundation. The availability of different nutrients can tell us a lot about the ecosystems former state and how adaptive it is currently.

I am trying to find soil data from native forests in the area, to compare the values. If you know someone or you found a source, feel free to post it in the comments or in the Ecosystem Clinic Chat.