Camponotus ants alongside plant-eating bugs on a cocoa plant in Ghana. Credit: David Hughes
Camponotus ants alongside plant-eating bugs on a cocoa plant in Ghana. Credit: David Hughes

The Plagues We’re Least Prepared For

If I asked you to name an infectious disease that has the potential to really screw us over, what would you pick? Maybe you’d choose flu, HIV or Ebola. Perhaps you’d name an upstart like MERS, or a more established threat like malaria or tuberculosis.

But how many of you named potato blight, rice blast or wheat rust? How many have even heard of cassava mosaic virus or black pod rot? Plant diseases don’t grab the limelight as readily as those that directly infect humans or other animals, but they can be equally devastating. They kill the crops we rely upon for both food and wealth, and they have a track record of crippling nations and changing the world.

In a long feature for Aeon, an exciting new online magazine, I look into the problem of plant diseases—one that we are grossly ill-equipped to deal with.

The story begins and ends in Ghana, where ants are coordinating a tangled web of pests and pestilence that threatens to bring down the country’s supply of cocoa—the plant that chocolate is made from. If Ghana loses that battle, the world’s chocolate supply would take a hit, and the country’s economic fortunes would crumble.

But I also look at other plant diseases, and how they’ve killed millions of people, shaped the history of entire countries, been used as weapons of “agroterrorism”, helped to install dictators, enshrined the British habit of tea-drinking, and showed us how microbes cause disease well before Pasteur’s famous experiments.

I discuss how we’ve lost many of the people whom we need to identify and study these diseases, and how our inability to learn our historical lessons has left our crops in an incredibly vulnerable position.

And I meet David Hughes, a scientist who has gone from studying fungi that break ant societies to diseases that break human crops. As an Irishman, Hughes is well versed with the ability of plant diseases to cause pestilence, death and famine. He’s now working to stop Ghana from suffering the same fate and, more broadly, to equip the world with the knowledge it needs.

I love writing this, and I hope you enjoy it.