By R. Gary Raham
People love to eat bananas. Daniel Workman reported at worldstopexports. com that the top 15 banana-exporting countries spent $13.6 billion dollars in 2018 feeding hungry clients. The United States’ share was $444.4 million. Virtually all the bananas exported are one species: the Cavendish banana. A fungus called Fusarium oxysporum TR4 also likes to consume the Cavendish banana, and once it lays claim to a plantation it can’t be controlled. Fungal spores remain viable for 30 years in the soil. The fungus began to show up in the 1990s in Malaysia and Indonesia and quickly spread to China. It also spread to plantations in Asia, Australia, and Africa. On August 8 of this year, Columbia declared a national state of emergency when the fungus appeared in that country’s banana plantations. Growers and sellers fear a banana apocalypse—not unlike one that occurred in the 1950s.
Yes, the bananas your grandparents ate were not the Cavendish variety. They ate Gros Michels, also called “Big Mikes.” Nathaniel Sharping, a science writer for Discover magazine, noted in a 2017 article that the Big Mike banana “was near-perfect for mass production. Tightly-packed bunches, thick skin, and a general durability made it easy to transport and the banana was sweet and creamy enough to keep customers coming back.” But a strain of Fusarium attacked this banana too. United Fruit, the company that made their fortune with this banana, managed to keep ahead of the fungus for a while by abandoning infected plantations, clear-cutting some more land in the Central American countries they used for production to plant new acreages, and then moving on when the fungus caught up to them.
Just when the fungus appeared to be on the verge of wiping out the industry, someone discovered the Cavendish banana hiding out in the greenhouse of a British Duke. The Cavendish not only fought off the fungal attack, but also had many of the endearing features of Big Mike (Tasty, with thick skin, ships well, grows easily from cuttings) United Fruit, now named Chiquita Brands International, survived into the 21st century with a diminished, but still lucrative, business.
But, as Scharping observers, “Today, that same tragicomic situation is playing out once again, and it appears we haven’t learned much.” The biological truth remains: if you invest everything in one species—and in the case of bananas, a clone of a single species—that species is vulnerable to catastrophic decline. In living systems, diversity is the key to survival. Randy Ploetz, a professor of plant pathology at the University of Florida described it this way: “Monoculture plantations of banana or any crop are a surefire way that if you’ve got a virulent pathogen out there, boy you’re gonna know about it because you’ve got this uniform population of suspect hosts.”
Are there solutions? Possibly. Rigid protocols for quarantining infected plantations, and practicing exacting methods to insure that fungal spores don’t arrive on dirty boots and farm tools can delay spread of the disease. Scientists have made some progress using new gene editing techniques to create transgenic bananas with built in resistance—but consumers in many parts of the world still balk at genetically modified crops. But the best prevention of such disasters surely lies in recognizing the value of maintaining diversity in our food crops—even if it costs more upfront. E. O. Wilson, the entomologist and elegant nature writer who invented the term biodiversity, has said, “Biodiversity is the totality of all inherited variation in the life forms of Earth, of which we are one species. We study and save it to our great benefit. We ignore and degrade it to our great peril.”