What Is Coffee Rust?
One of the biggest threats to coffee around the world is coffee rust. This disease threatens every major coffee producing country in the world. So what is coffee rust? What does it do to coffee plants?
Is this a new issue? What is it?
Is coffee rust a new disease for our favorite plant? Well, sort of. The first reports of coffee rust came from English explorers in East Africa as far back as 1861. As such, this isn't necessarily a new disease, and it was quickly reported in other parts of the world as well. But what is coffee rust? Why do we call it that? It turns out that the name makes a lot of sense!
Most Coffee Rust is a fungus called Hemileia Vastatrix. Another strain of the fungus, H. Coffeicola, is exclusively found in West and Central Africa. Both of these fungi create a distinct yellow-brown ring of lesions on the leaves of the plant. The appearance of these lesions are what gives coffee rust its name. It makes the leaves look like they are rusting. What sort of damage can this disease do?
Because Coffee Rust is a fungus, it can quickly spread and destroy vast swaths of plants. The easily spreading disease can be devastating to individual harvests and the long-term health of a plantation. So what can be done to stop this disease?
Spread and Management
It is nearly impossible to save a crop once the Rust has developed. This means that the safest means of managing a Rusted crop is to quarantine it. This means ensuring that local farmers know not to remove any plants from the area, first and foremost. It is believed that the spread of this disease is carried out on the wind. This means that the only true barriers to the spores are large open areas like oceans. This is why it's extremely important for plant importers to check their plants for lesions before accepting the plant. Crops of infected plants are generally killed with herbicide to prevent their spread. It is also common practice to kill surrounding plants as well, so that the spores have nothing to cling to. The hope is that the colonies of fungus will die off before they can be carried to another plantation.
There are some fungicides that can help prevent Coffee Rust. Application during wet seasons can help prevent spores from taking hold. Higher, cooler plants and those in shade are also less susceptible to the disease. Unfortunately rising global temperatures will likely eliminate this advantage. Some resistant strands of Robusta coffees have been developed, but these are often viewed as lower quality for consumption.
Because this is such a global issue, many researchers are seeking ways to stem the tide of this disease. While continued climate change puts more plantations at risk, hope exists in developing technology to identify and eliminate spores before it's too late!