Cavendish bananas face extinction and not all experts agree on how to save it

• Cavendish, the most commonly available banana variety, is facing the risk of extinction.
• A fungus that ravages roots is gradually eradicating Cavendish from banana farms all over the world.

Each year, humans worldwide eat over 100 billion bananas, most of which are a type called the Cavendish. But perhaps not for long.

A fungal disease threatens to wipe Cavendish bananas off the face of the Earth. Some scientists are genetically modifying the fruit to be more resistant to disease.

But the best solution to the problem, some argue, is for farmers to completely overhaul banana production and stop growing only one variety of fruit altogether.

Why Cavendish bananas dominate the global market

There are over 1,000 varieties of bananas, but about 47% that humans eat are Cavendish bananas (Musa acuminata).

Cavendish dominates the global banana market for several reasons. One, it's resistant to some of the major banana-killing diseases; two, it has a long shelf life; and three, farmers can typically grow more Cavendish bananas than other varieties on the same amount of land.

"Because of all these reasons, Cavendish becomes a very practical product," journalist Dan Koeppel, author of the book "Banana: The Fate of the Fruit That Changed the World," told Insider.

But the Cavendish is under threat from a fungus that infects the plant. The infection is called Panama Disease (Fusarium wilt) tropical race 4.

TR4 infection starts in the banana tree's roots and then spreads, ultimately disabling the plant's ability to absorb water or conduct photosynthesis. Eventually, the tree dies as a result.

Panama disease is a serial banana killer

What's happening to Cavendish bananas has happened before to another popular banana variety called Gros Michel.

Gros Michel was the "main export banana in the first half of last century," James Dale, a professor and leader of the banana biotechnology program at Queensland University of Technology, told Insider.

But a predecessor to TR4, called tropical race 1, began infecting bananas in 1876. By the 1950s, it had completely decimated Gros Michel farms, forcing banana producers across the globe to look for a new variety.

In the following years, "Cavendish became the leading export banana replacing Gros Michel because it was immune to TR1," Dale added.

In 1997, scientists detected a new strain (TR4) near Darwin, Australia, that infected Cavendish. By 2015, it had spread to the banana farms in Queensland, the largest banana-producing state in Australia.

"Since then it has spread to India and China, the world's largest producers of bananas. It has also spread to the Middle East and Africa and very recently was found in South America," Dale told Insider.

How scientists are trying to save the Cavendish

Some plant pathologists don't believe that the Cavendish banana will meet the same fate as Gros Michel.

"The disease moves slowly, so we have at least a decade before the impact is drastic," Dale said.

Also, many scientists are working on TR4-resistant Cavendish or a resistant replacement for Cavendish.

For example, Dale and his colleagues have developed a genetically modified Cavendish called QCAV-4, which they said is highly resistant to TR4.

Another research group led by scientists at the University of Cambridge is exploring grafting as a possible solution. Grafting tissue from one plant onto another can alter certain characteristics of that plant, like making it more resistant to disease, per the University of Cambridge.

Another team at the Taiwan Banana Research Institute is attempting a form of natural selection. The team takes Cavendish seedlings and exposes them to TR4. The small portion of seedlings that fair best then go onto additional experiments to ultimately help the Cavendish evolve to become resistant to TR4, absent of genetic modification.

"I would say with certainty that there will be a solution before the export market for Cavendish is severely affected," Dale added.

But some banana experts argue that such solutions won't work long term.

There's no single solution to the problem

"It's true that there is some resistance, but I'd say right now, nobody is even close to solving the problem," Koeppel told Insider, adding "The answer is going to be the end of monoculture. The answer is variety."

He suggests that replacing the current banana cultivar with a new disease-resistant variety is a short-term solution because the fungi can also come up with a new and more powerful strain in the future.

The real solution is to mass produce and sell more than one banana variety because the more genetically diverse bananas are, the less likely they'll be susceptible to diseases, he said.

Plus, it would also reduce the dependence of humans on one type of banana.

"Apples are a huge example of this. Today If I go to any supermarket in the US, I will find between five and 30 apple varieties," Koeppel said. "Apple growers are going nuts trying to introduce new varieties naturally as well as through hybridization, and genetic modification."

This reduces the risk of disease, offers more variety to customers, and as a result, "apple growers are still making a lot more money because of this," he said.

The problem with bananas, Koeppel said, is that there are far fewer varieties, and they're all cheap.

"If you add variety, the investment will pay off very quickly because suddenly some people will pay $4 a pound for certain bananas," Koeppel told Insider.

Dale, on the other hand, isn't so sure. "Price is the driver," of banana sales in his country Australia. He added, "Most people will purchase Cavendish because it is cheap."

Introducing a wider variety of bananas would not only drive up costs but would also require a major overhaul in how we transport bananas — since you can't just store them in freezers for long periods like apples, Dale said.

"The export market is dependent on harvesting Cavendish green and then inducing ripening by ethylene gassing. This is done during transport and is very tightly controlled and tailored to Cavendish," Dale said, adding, "If there were multiple varieties of bananas exported then it is likely that each would need specific defined ripening conditions. And of course the price would increase."

There seems to be no single solution to the problem that's working, so far. Perhaps history is bound to repeat itself and Cavendish will no longer be the banana of choice in the near future.