The banana in your lunch sack has a name: the Cavendish banana. It's the most common banana grown for export and it's part of a $40 billion global industry.
Until the 1950s, the dominant banana was another variety with another name: Gros Michel, a hardy fruit that shipped well and grew easily. But Gros Michel had an enemy — a soil-born fungus called Race 1. About a hundred years ago, Race 1 nearly destroyed the banana industry. According to Emily Monosson in her book Blight Fungi and the Coming Pandemic, the fungus quickly killed the Gros Michel plants, setting growers off on a search for a replacement banana.
The banana they found was the Cavendish. The Race 1 fungus didn't like the Cavendish, which was very close to Gros Michel in terms of flavor and appearance, but it had a drawback. The Cavendish is extremely delicate compared to the Gros Michel and expensive to export. But with the looming demise of the commercial banana, the industry changed to accommodate Cavendish, carefully protecting the fruit as it grows and shipping it in boxes.
When Cavendish finally arrives at the grocery store, it is likely labeled 'sustainably grown.' But that may not be entirely accurate. Another fungus has arrived: Tropical Race-4 (TR4) threatens to wipe out the Cavendish plant entirely, along with the economies of multiple Latin American countries with it.
TR4 is nearly impossible to eliminate. It is resistant to chemical fungicides and can survive in the soil for more than 20 years. It can spread rapidly, hitching rides on boot soles or in flowing water.
Large industrial growers with more resources and high-tech processes in place (like the sterilization of boots) have been able to control the fungus. But it's still bad news for small organic growers whose farms are more susceptible to infection.
The solution may come in the form of genetic modification or microorganisms that help bananas fight the fungus. A change in farm practices might also help, such as introducing more biodiversity into massive banana plantations.