The cultivar of banana that you and I enjoy from the grocery store is not nearly the same as the bananas found on shelves as late as the 1960s. The “Gros Michel” banana was the only cultivar of banana produced in mass quantities in the nineteenth and early twentieth centuries. The Gros Michel began its steady decline in 1910 when scientists discovered a fungus in the soils of many banana plantations. This fungus, named Panama Disease after its rapid spread through that banana-growing region, spread quickly through disease-ridden planting material and caused the Gros Michel to go effectively extinct by the 1960s.
Luckily, there was another cultivar of banana that was being kept in the United Kingdom Botanical Gardens and national fruit collection in Honduras: the Cavendish banana. Though not nearly as rich in taste, the Cavendish banana was resistant to the first strain of Panama Disease. Little did the industry know that there would be a total of four races of Panama Disease with multiple strains. In a lapse of judgement, the worldwide industry thus began replanting the same variety of banana year after year on the same area of land, known as monocropping, the Cavendish. This is the banana that we still eat today.
It did not take long for the Panama Disease to evolve into a new strain that could attack the Cavendish cultivar. In 1994, the cause of this new strain of the fungus was recognized as Tropical Race 4 (TR4), a cloned pathogen that is part of the fourth race of Panama Disease. This was especially bad news for the banana industry this time around because there were no back-up cultivars and because TR4 was an evolved strain that attacked even the more local of banana varieties.