We Let Bananas Go Extinct Again Quiz

Answer: False

The Gros Michel is extinct - not biologically, but economically. In the 19th century, the Gros Michel (nicknamed through translation "Big Mike") was stricken with a blight called Panama disease, caused by a fungal microbe in the genus Fusarium. Although the plant was not entirely killed, all Gros Michel plantations were wiped out by 1960. The major cultivar which replaced the Gros Michel is the Cavendish, but it, too, is susceptible to other strains of the same fusarium fungus.

You can try a Gros Michel, if you really want to, but you'll probably have to travel to Thailand, Hawaii, or the Caribbean, where small quantities of the fruit are still grown. While they're among the cornucopia of bananas Southeast Asia enjoys, the Sandwich Islands have capitalized on "original" bananas as a tourist attraction. It's one banana - what could it cost? A single Gros Michel on Hawaii can cost over $10.

Answer: Acidic rain water

The culprits in our story are two "races" of Fusarium oxysporum, the fungus that causes Panama disease. Many kinds of plants can be infected by various Fusarium species (barley and sweet potato among the victims), but bananas are hit especially hard because of their lack of genetic diversity and the dense plantations in which they are grown. A field of bananas is a thick monoculture, with no room for other vegetation to grow in between the crop. This makes them a particularly easy target for the fungus.

Mature banana plants naturally produce five to twenty suckers, offshoots that can be replanted. These cuttings are all genetically identical, meaning that all Cavendish bananas will be susceptible to the same diseases. This same vulnerability led to Big Mike's decline. An unrelated pathogen called black sigatoka is also a fungal disease, though it attacks leaves, not the entire root system, and there are at least chemical agents that somewhat mitigate its damage.

Answer: Taiwan

Cavendish resists "race 1" of F. oxysporum, which causes the Panama disease that whacked Big Mike. Tropical Race 4 was found in the early 1990s in Taiwan. It has since spread through Indonesia, Malaysia, China, the Philippines, Australia, Mozambique, Jordan, Pakistan, and Lebanon... so far. According to an article in Nature, TR4 "now poses a very significant threat to commercial banana production worldwide and, together with race 1, severely limits the number of banana cultivars suitable for either large scale or smallholder production."

Peter Chapman, who has literally written the book on "Bananas," calls banana "the world's fourth major food, after wheat, rice, and milk." Having looked at the UN's Food and Agriculture data myself, I feel that this banana expert has overstated the importance of bananas, but not by too much: the world gets more of its calories from bananas than beans, fish, apples, onions, and citrus.

Answer: Cavendish bananas cannot reproduce through their seeds.

It is true that the Cavendish banana is extinct in nature, but it goes further than that. Cavendish bananas are as sterile as mules - alas, those agronomically-desirable tiny seeds also prevent bananas from attaining genetic diversity. Rather than the economic "extinction" discussed earlier, this genetic sterility is called "functional" extinction. The only way to make more Cavendish plants is to clone them, either by replanting a sucker or growing a new banana plant from banana tissue.

In fact, many varieties of produce need to be genetically cloned to prevent taste variations. If you plant a McIntosh apple seed, it won't taste like a McIntosh (you'll probably get a crabapple), but if you graft it onto another plant, you will get McIntoshes.

It is more accurate to say that plantains are a "cooking banana" (both belong to the genus Musa). While the difference has always been emphasized where I'm from (probably so young me wouldn't bite a mouthful of raw plátano), in other places, like Africa, both plantains and "dessert" bananas are regularly cooked. Interestingly, plantains are far more resistant to fusarium and TR4 specifically.

Answer: Give up growing bananas on that land entirely

You can't extract it, burn it, drown it, dry it, poison it, salt it, cut it out, get something to eat it, starve it, distract it, attack it with bacteria, or outcompete it. No fungicidal control for fusarium is known (not that this has stopped snake oil salesmen from claiming to have THE solution.) Nor can you do anything to save a blighted plant: the wilt spreads completely through the length of the plant. Even leaving and coming back later isn't a viable option: the fungus can survive in infested soil for half a century, if not longer.

At the local level, banana farmers destroy the plants, isolate the fields, and attempt to disinfect their farm equipment. There is doubt that these measures can even slow fusarium, and we know it won't stop it. Cultures have been preserved of the Cavendish to preserve it into the far future, in the inevitable event of a mass die-off. But even if we simply accept that we'll be without the Cavendish for 50 years, until our soil rejuvenates, we'd just be facing another fungal epidemic some time down the road.

Answer: 1960s

Panama disease was first detected in parts of Central America towards the end of the decade of the 1900s. Panama disease took about 40 years to wreak its devastation; most United Fruits plantations were abandoned by the 1950s. Luckily, an upstart was at hand to replace it: a variety first described in the greenhouse of a British nobleman, William Cavendish.

It was not the kind of epidemic where growers woke up and found their plants spontaneously eradicated. Fusarium kills slowly. In other words, it's quite possible we are already living through the last days of the Cavendish. The effects of Tropical Race 4 have already begun to hinder yields in the Philippines, and it may well be only the beginning. In 2000, there were already those who believed that bananas would go extinct by 2010. In the future it may be they, not we, who are laughing.

Answer: Venezuela

The Banana Wars are a story that would take several quizzes to tell. The capsule version: United Fruit (now Chiquita) was one of the first corporations to act on a truly global scale, forming friendships with governments from Central America down into Colombia. Backed by the U.S., Chiquita had more power than the banana republics themselves. Speaking of a Bogota militia's massacre of striking United Fruit workers, a U.S. diplomat said: "I have the honor to report [...] that the total number of strikers killed by the Colombian military exceeded 1000."

At one time, United Fruit controlled 90% of the banana export trade. Almost all its enormous plantations were within contiguous regions of Central America. This, Chapman says, was a "graphic invitation to disaster." Union Fruit's heightened aggression during the 1910s can be chalked up to fusarium. Panama disease struck United Fruit's plantations in the early 1900s and, by 1909, Honduras, the only manipulatable nation left, found itself in the Chiquita crosshairs. They erroneously believed that the alkaline soils of Honduras were protected from fusarium, an assumption proved cruelly wrong by 1930. United Fruit tried Guatemala, Ecuador, Chile... all to no avail. They left the blight, but took with them wealth, equipment, and prospects - which was just as much a devastation.

Answer: Infected planting material

Fusarium oxysporum spreads through infested soil and planting media. While this sounds manageable, it's hard to imagine a more frustrating vector. Black sigatoka, the leaf disease we mentioned earlier, is an airborne vector, yet its spread has not been nearly so frustrating. Soil sticks to trucks, shoes, equipment, animals, and to the roots of young plants that have been replanted.

The fungus can spread even farther via water, and thus a microscopic fusarium culture can grow to infect an entire field.

Answer: False

Even if we imagine every living Cavendish plant is wiped out, there are other banana varieties, such as the aforementioned plantains, that are not affected by TR4 in particular. Only about 40% of global banana production is Cavendishes, but virtually all of the export trade is. The danger is not to the entire banana genus, Musa, but rather to the economic viability of bananas as we know them. Over a century ago, United Fruit were instrumental in bringing the exotic banana to Europe; perhaps small localities are where the banana is meant to stay.

It is true that there's been enormous difficulty in finding a sustainable replacement to the Cavendish. The banana world's also-rans are lacking in flavor, hardiness, or resilience to other diseases. By the way, that criticism has been leveled at the Cavendish as well. Its flavor is agreed to be slightly less complex than the Gros Michel, although in some blind taste tests, some participants seem to prefer the blandness.

Answer: Non-transgenic

"Transgenic" gene modification transplants genetic data from one organism into another. In the case of Cavendishes, the bananas have been made more fungus-resistant by inserting genes from other plants: wild bananas, rice, and even peppers. While this works, much of the world bans or heavily regulates genetically modified organisms (GMOs) due to safety concerns, and so the search is on for a "non-transgenic" source of resistance, such as through use of CRISPR (DNA sequencing) technology. CRISPR modifications only change existing DNA; for this reason, they are less regulated, as they're considered similar to selective breeding and natural mutations.

(I'm aware that the danger level of GMOs is extremely contentious, so I'm hoping you'll agree to call them "safety concerns," since, regardless of whether or not it's valid, people definitely are concerned.)