Until 50 years ago, the world's export banana was Gros Michel. Said to taste better, last longer, this cultivar of bananas was resilient and did not require artificial ripening.  As relayed in CNN, in 1965 this banana species became commercially extinct because of a fungal disease, the Panama disease, that started in Central America and which spread across the world's commercial plantations. The disease affects the vascular system so that the banana plant is unable to absorb water. With no other alternative but to burn all the infected plants, the banana industry was thrown into a quandary until it found the new cultivar for world export.  

Although inferior to the Gros Michel, the Cavendish species was quickly adopted worldwide by banana growers for its distinction of immunity to the Panama disease.   Out of hundreds of banana species in the world, the Cavendish is the only cultivar that dominates total banana exports each year. It has effectively pushed out a lot of the other banana species.

The problem is that the Cavendish is also a monoculture so that that these bananas almost have no genetic diversity and is the only banana variety that the majority of commercial banana planters grow every year. This characteristic in itself is what poses a major threat to the Cavendish.  A disease that infects one variety of Cavendish will infect all.

A new strain of the Panama disease, now known under a new name as Tropical Race 4 (TR4), was initially found in Malaysia in the 1990s.  Unfortunately, the Cavendish is not immune to this strain. Since then TR4 has spread to Southeast Asia and onto Australia.  It has also been discovered in the Middle East.  Beginning 2013 the disease became a growing threat in Africa.

Author of the book 'Banana: The fate of the fruit that changed the world' Dan Koeppel explains, "It is 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."

Senior plant pathologist George Mahuku of the International Institute of Tropical Agriculture says, "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."

According to Koeppel practices from 50 years ago by banana growers, which allowed the spread of the Panama disease, are still in place.  Standard agricultural quarantines and cleaning equipments are insufficient to prevent disaster.

Smithsonian Magazine relays Koeppel's statement to Scientific American, "And as of now there is no cure, and when it comes it will go fast and it will go very devastatingly, will probably wipe out the entire banana crop, unless something is done about it, unless some kind of cure is found or unless we diversify our banana crop before that."