How El Toledo Coffee Farm Beat a Devastating Fungus…Without Chemicals

Starting in the 1990s and continuing until today, the Calderon-Vargas family of Costa Rica has lost at least 5% of their coffee yield every year to a pest known as the rust fungus. The conventional farms surrounding them lost none to it…ever.

It’s not hard to see how the rust fungus got its name

The fungus doesn’t actually attack the coffee berries. Instead, it feeds off of the leaves that grow next to the coffee, providing shade that allows them to ripen at a healthy pace.

When the leaf dies because of the fungus, it falls off the coffee tree prematurely. Without the requisite shade, the coffee ripens too quickly, leading either to a low quality bean, or a cherry that falls to the ground and is essentially lost for good.

Adding Insult to Injury

This was a particularly cruel development for the family. Already, they had been forced to give up conventional farming altogether: their patriarch — Gerardo — developed debilitating stomach and neurological problems as a result of the chemicals.

While they believed a certification in organic farming could help stem the loss of revenue, their harvest dropped an astounding 80% when all the inputs were removed. In order to make ends meet, the family got jobs in a number of different industries.

El Toledo is more like a rain forest outside of the dry season.

And yet, even though the family could have used “organic” fungicides to control the rust fungus, they chose not to.


I’ve already covered the long version, but Gabriel — Gerardo’s son who offers tours of the farm — describes it succinctly:

“We believe in the balance and wisdom of Nature. We rarely understand how it works, but through the years, we’ve discovered that it’s usually best to let Nature figure things out instead of interfering.
If that balance is accomplished by losing 5% of our coffee every year, then that’s the price we’re willing to pay.”

A Crisis Brewing

Most people would hear that explanation and shake their heads. It is, after all, exceedingly rare to hear a farmer talk about trusting Nature. That reaction didn’t bother the family too much: by 2010, the farm was back to producing enough coffee that they could sustainably live on the yield.

But then, circumstances changed dramatically…for everyone but El Toledo.

Starting in 2012, the rust fungus hit Central American farms with a vengeance. Some farms in these countries lost as much as 50% of their yield almost overnight.

But on El Toledo itself, the drop topped out at about 11%. Why, when all of the farms surrounding them went from losing nothing to the rust fungus to losing 50%, did El Toledo see such a muted response?

This was the question that Gabriel put towards the tourists visiting his farm. One-by-one, they would go around offering up smart-sounding answers.

Gabriel Calderon-Vargas giving a tour at his family’s coffee farm

Eventually, the tourists would finish giving their guesses, and eyes would turn back to Gabriel, with bated breath to hear the real secret behind El Toledo’s resiliency. His answer:

“I don’t know. We trust Nature, and the balance it provides.”

I like to refer to that as the “spiritual” answer to the question. But when scientists came to study the phenomenon in 2014, we got a scientific one as well.

If you inspect a rust-infected leaf from El Toledo close enough, you’d notice a faint white fungus was also (apparently) feeding on the leaf. It turns out that this white fungus was the natural predator to the rust fungus.

On all the other farms around them, chemical fungicides had indiscriminately killed off both the rust and white fungus — much how chemotherapy doesn’t just target cancer cells, but kills everything in its path.

The problem is, the rust fungus mutated; it developed an immunity to the fungicides. All it took was that one Black Swan event to wipe out huge swaths of coffee.

Monocultures are exceedingly fragile to Black Swans

Because the white fungus did not mutate, and because all of these farms were largely monocultures, there was absolutely nothing standing between the rust fungus and the coffee plants.

Except, of course, for El Toledo. Because of the family’s decision not to combat the yearly 5% loss to the rust fungus, the white fungus was alive and well on the farm. Additionally, because the family had largely, “given the farm back to nature,” there were lots of other plants for the rust fungus to go after.

By no means did El Toledo eliminate the rust fungus — indeed, when the crisis hit, it’s losses more than doubled. But by practicing diversity, it had contained it.

Roasting coffee at El Toledo is a group event

There’s a crucial lesson in this for everyone: if we try and optimize our systems to get maximal production, our agricultural systems become fragile to the slightest disruption. By building in redundancy, and by allowing Nature to establish a balance, there are margins of safety built in.

El Toledo will never produce as much as conventional farms in its best years, but it will probably never have another bust year that threatens farmers with bankruptcy either. That security, plus the host of advantages that this type of farming have for the world, is an encouraging message to spread.

*The percentages used in this piece aren’t the most precise, but demonstrate the general principal at play.

*Much of the philosophy behind this piece comes from Nassim Taleb’s work

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