You can enable subtitles (captions) in the video player
Dire warnings about bananas' impending extinction have been circulating for some time. Even so global production has expanded in recent years, from estimated annual volumes of 69mn tonnes in 2000 to 2002, to 115mn tonnes in 2017 to '19. That growth, however, is at risk.
The latest outbreak of Panama disease, also known as Fusarium Wilt, is caused by a fungus, specifically the TR4 strain of Fusarium oxysporum, which has spread to at least 22 countries. It kills by attacking plant roots, blocking the flow of water and nutrients. Resistant to chemical treatments, its spores can survive in contaminated soil for decades and can be spread by people, animals, machinery, and stormwater.
With more than 80 per cent of all bananas, including plantains, thought to be susceptible, the disease threatens the livelihoods and food security of an estimated 400mn people. It's particularly contagious among Cavendish banana varieties which account for almost all exports and stocks on supermarket shelves.
Cavendish bananas are clones reproduced from offshoots, so each generation is identical. While the uniformity may appeal to consumers, the lack of natural variation means there is no immunity when infection strikes. TR4 has caused estimated annual losses of $388mn in China, Indonesia, and Malaysia alone.
A different strain of the Fusarium fungus toppled the world's last dominant banana clone, Gros Michel, or Big Mike, in the 1950s. The unaffected Cavendish was a convenient replacement then. But now it's highly vulnerable and this time there's no viable alternative. Some resistant plants have been created by removing genes that make established varieties susceptible or inserting protective genes from wild bananas.
But genetically modified crops remain controversial, banned, or subject to long-term safety trials and regulation in many regions. One UK research group claims to have developed a seed-based grafting technique to introduce fungus-proof traits into Cavendish varieties. But botanists and environmental scientists argue that the best solution is to diversify and move away from monocultures.
There are more than 1,000 known types of banana and, according to a recent study, at least three as yet undiscovered ancestors of domesticated varieties to consider.