Baku, August 2, AZERTAC 

They tasted better, they lasted longer, they were more resilient and didn't require artificial ripening. They were -- simply put -- a better fruit, because they belonged to a different species, or cultivar in banana parlance.

It was called Gros Michel and it remained the world's export banana until 1965.

That year, it was declared commercially extinct due to the Panama disease, a fungal disease that started out from Central America and quickly spread to most of the world's commercial banana plantations, leaving no other choice but to burn them down.

The banana industry was in deep crisis, and had to look for alternatives. It settled with the Cavendish cultivar, which was deemed an inferior product but carried the distinction of being immune to the disease. It was quickly adopted by banana growers worldwide.

Today, the Cavendish is a universal foodstuff, much like a Big Mac: supermarket bananas are pretty much identical anywhere you buy them.

That's because they have nearly no genetic diversity -- the plants are all clones of one another. The Cavendish is a monoculture, which means it's the only variety that most commercial growers plant every year. Which is also why it is now under threat itself, from a new strain of the Panama disease. And once it infects one plant, it can infect them all.

Fifty years on, one of the most popular commercial foods in the world is once again under threat.

There are hundreds of banana varieties in the world, but the Cavendish alone accounts for nearly the totality of exports.

"Starting in the late 1980s, banana growers realized more diversity was needed to prevent the problem from happening again. They were begging their bosses for it, but it never happened," Dan Koeppel, author of the book "Banana: The fate of the fruit that changed the world," told CNN.

The disease now has a different name, "Tropical Race 4," and it started out in Malaysia around 1990, but it's otherwise very similar to the one that wiped out the Gros Michel: "It's caused by a really common type of fungus called Fusarium, which was probably already in the soil there. A single clamp of contaminated dirt is enough to spread it like wildfire, and it can be transported by wind, cars, water, creating an infection wherever it goes," explained Koeppel.

"Everyone who's ever had athlete's foot knows how hard it is to get rid of a fungus."

The pathogen affects the plant's vascular system, preventing it from picking up water.

Since its "second coming," TP4 has spread to South-east Asia, then across thousands of miles of open ocean to Australia and finally, in 2013, to Africa.

"Its recent discovery in the Middle East and in Nampula, Mozambique, indicates that the disease is spreading and threatening bananas worldwide," George Mahuku, Senior plant pathologist for the International Institute of Tropical Agriculture, told CNN.

"It's a serious threat to livelihoods and food security in the Nampula province, country and the continent, should it spread. In Africa, bananas are critical for food security and income generation for more than 100 million people," he added.