Fast-spreading fungus could drive bananas to extinction

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(Did you know?) 4 years ago

Imagine a world with no bananas: no banana for breakfast smoothies, no peanut butter and banana sandwiches at lunch and no banana splits for dessert.

This tragic scenario could soon be a reality.

A deadly fungus that plagued banana plantations in Southeast Asia for 30 years has made the inevitable leap to Latin America, where much of the world’s bananas are grown.

The Colombian Agricultural Institute confirmed on Aug. 8 that it had found a strain of the Fusarium oxysporum fungus, called Tropical Race 4 (TR4).

Feds declared a national state of emergency, ordering farmers to quarantine plantations and destroy crops in the north, where the fungus was discovered.

“What we’re having is an almost apocalyptic scenario where we’ll probably lose Cavendish [the most widely cultivated banana] as well,” Sarah Gurr, Exeter University’s chair in food security, told Wired.

“Once it’s in a country it’s very hard to get rid of it,” added Dan Bebber, a bio-sciences lecturer at Exeter.

The current plight of the banana has a familiar historical arc.

Before the mid-20th century, wild banana varieties existed aplenty, grown around the world, each with unique flavors, textures and colors. But as industrialized agriculture boomed in the early 1900s, only the strongest and most prominent type was selected for the purpose global banana domination — the Cavendish banana.

At the time, the Cavendish was the only type of banana formidable enough to replace the prior reigning champion banana, the Gros Michel. Those were being wiped out by — you guessed it — a proto-strain of the Fusarium fungus.

Unfortunately, as nature has demonstrated time and again, the lack of genetic variance does a species no favors, and the once-hardy Cavendish is now being threatened by its own plague.

The disease was first discovered in Taiwan in 1989, followed by other Western Hemisphere Cavendish banana producers such as Lebanon, Israel, India and Australia. The disease spreads in the soil, easily transmitted via tractor tires, work boots and replanted specimens. TR4 can lie dormant for years until it’s soaked up along with water through the plant’s roots, and then starves the banana of nutrients.

Considering the infection can go undetected for some time, it’s difficult to know how widespread it is already. Farmers have tried to contain the pathogen by destroying crops, quarantining farms, and diligently cleaning farm equipment and the people working there. None of it worked: In 1997, a TR4 outbreak hit Australia’s Northern Territory, and the fungus has since spread north to Queensland.

Bebber predicts a “rapid spread” throughout Latin America. Some scientists are looking to gene-editing as a potential solution, or cross-breeding with other bananas to produce a more robust fruit.

But for now, the spread of the disease could mean the end of bananas as we know them. Scientists say it’s a wake-up call for the modern farm industry.