One of the single largest threats to coffee the world round is coffee rust, a disease which threatens all of the primary coffee producing countries of the world.

So what exactly is coffee rust, and what exactly does it do to coffee crops?

Is coffee rust a new problem? What is it?

As for whether or not it is a new disease, the best answer we can five would have to be “sort of”, but it depends on how extended your sense of history is.

The earliest reports of coffee rust were made by English explorers who were in East Africa in 1861. For many people, this will sound like a very old disease, but actually with respect to the life of the coffee plant throughout history it is a relatively new development.

So why is it called “rust”? Most of what we call coffee “rust” is a fungus known as hemileia vastatrix. The second most common strain of fungus, found exclusively in West Africa, is likely the one called h. coffeicola.

Both fungi manifest themselves in yellow-brown, rusty coloured rings of lesions on the plant’s leaves. If you look up a picture of leaves affected by this fungus, you will see right away that it does indeed appear that the plants leaves are rusting.

What kind of damage can this rust do? As a fungus, coffee rust can spread very quickly and destroy large quantities of plants at an alarming rate. It is not surprising for an outbreak to ruin an entire harvest, and even compromise the future health of the entire plantation.

What can be done to stop the spread of this disease?

Unfortunately, once the rust has developed it is very unlikely that the crop can be saved, meaning that quarantine is the only means left to manage it in order to stop it from spreading to other crops.

First and foremost this means making sure that local farmers do not remove any plants whatsoever from the infected area. Unfortunately coffee rust is an airborne disease, and even quarantining may not be enough to prevent the spores from riding the winds.

This is why it is extremely important for plant importers to check their plants for lesions before accepting any of them.

Infected crops are usually killed off entirely using herbicide to keep the spores from spreading, and in some cases even the surrounding crops of plants are killed off as well so that the spores have nothing nearby to jump onto.

In this way one hopes that the colonies of fungus will die off in isolation without spreading any further out from the area where they were originally discovered.

Some preventative measures do exist, however, such as the application of fungicides during the wet seasons which may prevent any spores from attaching themselves to the plants in the first place.

Plants grown in higher, shadier, or cooler areas are also less likely to develop the disease (though with global temperatures rising this advantage may soon disappear).

Some strands of Robusta coffee that are resistant to the disease have been developed, but unfortunately the coffee produced from these strands simply isn’t as good.

Many researchers are working on methods to fight back against this disease, which has now become an issue worldwide.

Though climate change is seeing more and more coffee plantations put at risk, there is still hope that new technologies will be developed in order to eliminate coffee rust for good!