Bye bye, banana?- A disaster of Monoculture

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Bye bye, banana?

Posted on August 18, 2011 by geobear7| 5 Comments

The Beginning of the End for Bananas?

Already reeling from a 20-year losing battle with a devastating disease, the banana variety eaten in the United States is now threatened by a new—but old—enemy.

By Dan Koeppel
The Scientist

Our standard supermarket banana, a variety called Cavendish, may be at the brink of disaster. Chosen for its resistance to a fungal pathogen that wiped out its predecessor, the Gros Michel banana, the popular fruit has long battled a related fungus, which has all but devastated the banana industry in certain parts of the world. Now, it appears the Cavendish variety is facing a new threat—the very same fungal disease that drove Gros Michels off the market.

Cavendish bananas account for about 45 percent of the fruit’s global crop, with an annual export value of US$8.5 billion, according to the United Nations Food and Agriculture Organization. It was chosen to replace the original Gros Michel banana after a deadly fungal infection, known as Panama disease (Fusarium oxysporum f. sp. Cubense), wiped out much of the world’s banana crop in the first half of the 20th century.

Farmers adopted the Cavendish variety because it appeared to resist the blight, as well as about a dozen other banana diseases that also threaten the worldwide crop. But it wasn’t long before it too started suffering from disease. In the late 1980s, a mysterious malady began to wipe out Asian Cavendish plantations. Soil samples were sent to plant pathologist Randy Ploetz of the University of Florida’s Tropical Research and Education Center, who made the shocking identification: Panama disease was back, in the form of a new strain, which he dubbed Tropical Race 4.

Race 4 is just as virulent to Cavendish as Race 1 was to Gros Michel. The fungus enters the plant via its roots through infected soil or water and spreads via the plant’s vascular system. Once exposed, the plant yellows, and begins to look obviously sick—dried-out, sunken, and sagging. As the disease progresses, brown and purple stripes appear on the trunk, and the plant eventually dies. The disease, however, lives on, spreading via infected soil from plant to plant, plantation to plantation.

Today the disease has spread across Asia, into the Pacific, and to Australia, where it has devastated the island country’s banana industry. Though Race 4 has yet to hit Latin America, where bananas imported to the United States are grown, there’s little doubt it will, said Ploetz.

But it turns out that Race 4 is not the only threat to Cavendish bananas. As banana growers have fled from Race 4, replanting their Cavendish trees in areas only known to harbor Race 1, they quickly learned that Gros Michel’s old foe was now tormenting Cavendish bananas as well.

In 2010, scientists conducting a survey of plants infected in India, which grows and consumes more bananas than any other country in the world, were the first to conclusively identify the presence of Race 1 in the Cavendish banana. They published their findings in Plant Disease that November, and this March, Bioversity International—the global umbrella group for banana research—released a report announcing the finding: Race 1 had begun killing Cavendish plants in plantations around the Theni District of Tamil Nadu, India.

Banana scientists are still trying to determine why some Cavendish are no longer immune to Race 1. Altus Viljoenm, a researcher with the University of Stellenbosch in South Africa, speculates that this new strain of Race 1 may have evolved over time so that it could attack Cavendish.

Other researchers are skeptical of the finding. Ploetz notes that there have been rare cases in which Race 1 has killed individual Cavendish plants when they were already stressed—due to drought conditions, for example, or flooding. “I suspect that this is the same thing,” he said.

But the authors of the Plant Disease paper reported that they had confirmed the finding with laboratory tests on sterile, potted Cavendish. “To our knowledge,” the researchers wrote, “this is the first report of [such] a virulent strain.”

Today, there are no cures, treatments, or even reliable molecular diagnostic tests for either Race, partly due to lack of detailed information on the banana genome, according to Bioversity. Currently, the best available strategy is containment. Ploetz has developed a plan to fight Race 4 if it appears in Latin American plantations, involving the use of strict quarantines on affected plantations to prevent, at least temporarily, the spread of the disease.

But isolating infected plantations is more a stopgap than a solution, Ploetz knows. “It buys time,” he said, but barring any new discoveries, the spread of Panama disease remains inevitable. Ploetz said it’s important that similar agricultural practices be instituted in already affected countries to help prevent the spread to Latin America in the first place.

In the meantime, scientists are working to develop new approaches to quell disaster. Last year, for example, University of Queensland researcher James Dale began the first field tests of a genetically modified Cavendish, which he hopes will provide long-term resistance against Race 4.

Banana companies such as Chiquita and Dole are also reportedly working to develop new varieties. Though genetic modification has long been considered the only way to breed Cavendish, since the variety is completely sterile, recent research conducted in Honduras has revealed that a few Cavendish plants do produce viable seeds.  Researchers at the Fundacíon Hondureña de Investigación Agrícola (FHIA) say these non-sterile fruit form the basis of a series of promising hybrids, that can be bred for resistance to the fungi. It will still be at least six years before the new breeds are ready to be brought to market, however, according to a source familiar with the project, or may never appear at all, now that the banana companies are no longer funding the research.

Most banana researchers agree that the real answer—as has been the case with crops like potatoes, apples, and grapes—is to abandon the monoculture that makes the emergence of a disease so devastating. A more diverse banana harvest would allow farmers to isolate susceptible bananas, surrounding them with more resistant varieties. If the solution ends up being a Cavendish stand-in that is resistant to both strains, on the other hand, the predicament of the banana monoculture—with its vulnerability to old, new, and yet-to-be discovered pathogens—would continue.

The Scientist’s Editor’s Note: This story has been updated from its original version to clarify that Bioversity International’s report merely announced the finding published in Plant Disease (that Race 1 had begun killing Cavendish plants in India), and did not perform any additional studies to confirm‎ the results.

Dan Koeppel is the author of “Banana: The Fate of the Fruit that Changed the World.” His account of a search, conducted in the Democratic Republic of Congo, for potentially diversifying banana breeds will appear in National Geographic in 2011.

c

Dan Koeppel

 

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"Banana: The Fate of the Fruit That Changed the World"

(Reviewed by Poornima Apte MAY 3, 2008)

   

Railroads being built through miles of dense forest, the invention of DDT, entire governments of countries engineered to collapse. All these seemingly random events are interlinked for the sake of one single, deceptively inexpensive commodity: the banana. These events came into being just to bring the fruit to the American table and if that fact seems totally improbable, it only confirm‎s the saying: truth is stranger than fiction.

In his expert account, Banana: The Fate of the Fruit That Changed the World, Dan Koeppel starts with placing the banana right at the very beginning of man's story. There is evidence, he shows, that the fruit that tempted Eve was not as most believe it to be, the apple—but the banana. In subsequent chapters, Koeppel shows how the fruit traveled around the world until one Cape Cod sea captain, Lorenzo Dow Baker, brought some bunches to American shores around the time of the country's centennial celebrations. At this early stage, the fruit was still an exotic commodity from the tropics. Bananas then were grown in Jamaica and transported over in relatively smaller batches than they are now.

The exotic fruit attracted the attention of a New England produce buyer, Andrew Preston, who found he just could not keep enough of the fruit in stock. Preston and Baker joined forces along with contributions of $2,000 each from a few other investors to bring more of the fruit to American shores. Together they formed the company Boston Fruit which is today the giant company, Chiquita.

To increase sales, Americans were fed a series of sharp marketing initiatives: coupons for a bunch of bananas were tucked into boxes of cornflakes; doctors who recommended mashed bananas to babies were encouraged.

Since bananas needed tropical climate, Latin America was the destination for the giant American fruit companies. After Aug. 12, 1898, the United States military intervened in Latin America twenty-eight times, Koeppel writes. “In Mexico; in Haiti, the Dominican Republic, and Cuba in the Caribbean; and in Panama, Honduras, Nicaragua, Guatemala, Costa Rica, and El Salvador in Central America. The biggest consequence for these incursions was to make the region safe for bananas.” American intervention in many of these countries was so severe and with such blatant disregard to essential labor rights, that the writer O. Henry “termed the nations that so readily acquiesced to the fruit companies and the U.S. Government as 'banana republics.'”

The original banana that Americans consumed, a variety called Gros Michel, was devastated by Panama disease. The fruit companies replaced the variety with the newer Cavendish but the problems that brought about Panama disease in the first place were still in place. Every Cavendish is a clone so the monoculture makes bananas still susceptible to the blight.

The story of bananas is very much a story of the sheer will and force of American capitalism. Wondering how to bring large quantities of the fruit to this country, refrigerated shipping was invented; when a brutal blight threatened to wipe out every last bit of the crop, new land was cleared and the fruit (with the disease) was simply moved; DDT and aerial spraying were invented to conquer the blight; labor uprisings in many South American countries were controlled by the fruit companies all with the companies' bottom line in mind. By the late 1920s, United Fruit had business interests in 32 countries. American consumers were encouraged never to put bananas in the refrigerator. A very famous Chiquita jingle from 1944 ended with: “Bananas like the climate of the very, very tropical equator; so you should never put bananas in the refrigerator.” This was an interesting irony especially considering the fruit companies  used refrigerated shipping techniques to bring bananas to American shores.

There are many varieties of bananas that are grown around the world. My own favorites are the really tiny bananas grown in India—each one is as long as a pinkie finger and is amazingly delicious. The taste, which is less sweet, is quite different from the American Cavendish. The Cavendish that is eaten here is being threatened by disease and Koeppel encourages Americans to look at all costs of the industrialization of food in general before making decisions about their survival. He also shows us the advances being made in the race to save different species of bananas.

While the banana has been researched and written about in earlier books, Koeppel's account of its history, discovery, travel routes and marketing strategies is unbiased and well-written. The facts come through loud and clear. Banana: The Fate of the Fruit That Changed the World is an eye-opening revelation of the true cost of a seemingly innocuous American staple. It manages to shine a harsh light on capitalism without degenerating into a polemic. You'll never again look at a banana without pondering its steep costs and improbable journey—and that will be a good thing.