Coffee, vulnerable to disease

As our trip to Colombia approaches, we wanted to talk to you about a rather worrying issue concerning the coffee we consume every day. Indeed, like most plants, coffee is constantly threatened by various diseases which, with climate change and globalization, are becoming increasingly devastating.

Rust

Coffee rust has been known for decades and has already wreaked havoc around the world. It is caused by a small fungus that attacks the leaves of the coffee plant, turning them an orange color, hence its name. The result? The entire tree can be destroyed by the leaves, preventing the production of the fruit and therefore the coffee.

Wondering why the British mainly drink tea? Well, it's partly due to a rust epidemic that struck Ceylon, now Sri Lanka and a former British colony. The entire coffee-growing industry had to be abandoned, cutting off all supplies to the British, who then turned to tea.

Rust first appeared in Central America in 1976 and since then has spread to several countries, notably Colombia since 2008. Several factors contribute to its development:

• The high temperatures observed in recent years allow the disease to survive and thrive even at high altitudes.
• Winds help the fungus to spread over long distances.
• The amount of shade provided to the plants must be taken into account. Plots in full sun are more susceptible to developing the disease compared to those in the shade.
• We cannot rule out the possibility that the disease has evolved over time, making it more resistant and aggressive.

The coffee bark beetle

The coffee berry borer is another significant threat to coffee production. This small insect (2 mm) of African origin is now present in all coffee-producing countries worldwide, with the Americas being the most susceptible. It attacks the coffee fruit directly, spending almost its entire life there. It burrows small tunnels, creating openings for other diseases, and even reproduces on a large scale. The result? The bean deteriorates, loses its aroma, and the fruit falls from the tree before ripening. The problem with the coffee berry borer is its close link to climate change: the warmer it gets, the shorter its life cycle becomes, forcing it to reproduce more and more.

Fighting diseases

There are several ways to fight diseases. Chemical treatment is obviously one, particularly with insecticides to combat bark beetles. But the disease adapts, and these treatments seem to be becoming less and less effective. Some biological insecticides

are also used: introducing into the cultures a bacterium toxic to the insect in order to eliminate it without altering the coffee.

We already talked about this a little in a previous blog post, Colombia has an advantage in the fight against coffee diseases: Cenicafé.

This branch of Fedecafé has been in place since 1938, and its goal is to develop knowledge and new technologies in the coffee industry. 38,000 different coffee specimens are preserved at Cenicafé and studied to combat diseases. Thus, in the early 2000s, Cenicafé created a completely new coffee variety: Castillo. Developed through years of genetic crossbreeding and testing, it is more productive and, above all, more resistant to coffee rust. Its cultivation began in 2005, but in 2011, the year of the worst coffee rust epidemic in Colombia, only 25% of the country's coffee trees were of this variety. Indeed, it takes more than five years for a coffee tree to reach optimal yield, thus delaying its introduction into plantations.

The future of coffee remains threatened. Diseases are adapting, becoming more resistant, and spreading faster. Castillo is already beginning to fail, with coffee rust managing to develop on this variety. Research is progressing, but agricultural practices will also need to change (shade management, fertilization management, and the elimination of chemical products) in order to save harvests and continue enjoying our cup of coffee.