China, like the rest of the world, now faces the distinct possibility that its beloved Cavendish bananas might become extinct over the next few decades.
A persistent, banana killing tropical fungus called "Panama disease" (Fusarium oxysporum f.sp. cubense) has been ravaging banana plantations in China, Asia, Africa, the Middle East, Australia and Central America for decades and is close to spreading out of control. Panama disease is a type of fungal infection that invades the soil and is lethal to Cavendish plants.
Scientists are concerned that should Panama disease reach South America (the world's biggest supplier of the Cavendish), this banana -- which accounts for 47 percent of bananas grown worldwide -- might face extinction.
The main reason why Cavendish bananas are almost completely helpless against Panama disease is they're genetically identical to one another. The fact the Cavendish is a monoculture allows Panama disease to rapidly destroy entire harvests. Unfortunately, Panama disease is resilient to fungicidal treatments, and infected fields are ruined once a single plant becomes infected.
The main threat to China's banana industry and the rest of the world is a deadlier mutation of the Panama disease called "Tropical Race 4 (TP4)" that started in Malaysia in the 1990s.
"It's caused by a really common type of fungus called Fusarium, which was probably already in the soil there. A single clump 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," said Dan Koeppel, author of the book "Banana: The fate of the fruit that changed the world."
The effects of this fungus on China's Cavendish crop have been devastating. Guangdong Province was once China's largest producer of Cavendish bananas with a cultivation area of more than 15 million hectares. Panama disease has reduced this growing area by half. Industry officials say the losses "are nearly impossible to evaluate."
To prevent the banana industry's collapse, Guangdong is promoting "Banana 9," the only Panama disease resistant banana variety in China. On the other hand, the rest of the banana producing world pins its hopes on the success of a rare Madagascan banana plant that's currently unpalatable but is immune to Panama disease.
Plant biologists are racing to develop a hybrid of the Cavendish and the Madagascan banana in the hope of creating an infection-resistant strain.
