Extinction of species is an unfortunate problem of homogenization. As we learn more about the environment, we as a society have begun to make changes in many areas of our life. We drive hybrids, have solar-powered garage doors, and recycle.
But yet, the food we eat is not often a topic of conversation. For years, horticultural experts have been warning about the potential demise — commercial extinction — of the humble banana. These so-called Cassandras were a bit ahead of the curve in terms of when this extinction was to take place, but the sad truth is, they are still right — the banana’s days are numbered.
There is only one commercially viable species of bananas. That means the entire banana crop is homogenized — all commercial farmers grow a single variety that has been proven to ship well while maintaining the best flavor. The problem with using a single strain of a plant species is that it leaves the entire crop vulnerable.
There is no diversity in the crop meaning that if something were to happen to this strain, bananas as a global commodity would become a thing of the past. One thing that science cannot do is predict how and when a virus or other pest will adapt to attack an organism. This is what has been slowly leading to the bananas demise.
A pathogen called Panama Race IV is responsible for irreparable damage to banana crops. This pathogen is so strong that it will kill an entire banana crop in a very short period of time. What makes this pathogen even more dangerous is that the land infected cannot be planted with the same variety of crop for thirty years.
And, recall, there is only one commercially grown banana variety. The only reason there still is a banana crop at all is that the virus has not yet reached all banana-growing regions, but many believe it is just a matter of time.
Globalization and international trade make the spread of this pathogen all the more likely and all the easier. The idea of the banana being unavailable is hard for most of us to imagine, but there could come a time when this is a sad reality.
This is a large-scale, global illustration of the importance of diversity in crop growing, even those for a commercial market. The more diversity there is in a crop, the more hardy it will be to threats such as these.
image credit: Amanda’s adventures
Are they taking any steps to deal with this problem? Do you know where we can find out more?
I can tell you more!
I am a scientist working on this very disease. Let me address a few points:
1) the disase is called fusarium wilt (commonly also called panama disease) and is caused by a fungus, not a virus. I’m not just being pedantic here; the difference between a fungus and a virus (biologically speaking) is astronomical.
2) the fungus is called Fusarium oxysporum f. sp. cubense, and is further subdivided into what we call “races”. Currently there’s race 1, race 2, race 3, and race 4. Race 4 is the really bad one.
3) amusingly enough (to get all battlestar galactica for a second) THIS HAS HAPPENED BEFORE, AND WILL HAPPEN AGAIN. In the early 20th century, the world ate a variety of banana called Gros Michel. It was THE commercial cultivar. And it was wiped off the face of the planet by fusarium wilt race 1.
What did we do? We replaced all the Gros Michel’s with Cavendish (which is resistant to race 1 of the disease). Everyone patted each other on the back, said “job well done!” and that was that.
In the 90s or so, race 4 popped up and has been slowly (but surely) ravishing bananas ever since. We currently don’t have any good (edible!) varities that are resistant to race 4, so if Cavendish goes (which it will), we’re a bit stuffed.
3) we didn’t get into this situation because plant patholgists and plant breeders are stupid. It’s because bananas are virtually impossible to breed…they don’t have viable seeds!
Usually (with other crops) if you a new disease pops up, you breed novel resistance into your commercial cultivars. But you can’t breed a banana without seeds!
4) it doesn’t actually kill bananas very quickly…it can take up to a decade for a banana plantation to succumb to the disease, but it WILL succumb…
5) you’re dead right about an infested field being impossible to replant. Fusarium is a crafty fungus…it can live in the soil (or lie dormant in the soil) for ages.
6) There’s currently three streams of research going on:
a) Genetically modifying Cavnedish to make it resistant to race 4 (there’s good progress in that field, but a deployable cultivar is still years away)
b) Soil ammendments, quarantine etc…that is, try and stop the fungus itself…or slow it’s spread
c) Breed a new commercial cultivar from scratch! Attemps to do that have been ongoing for decades (you may remember Goldfinger bananas? They were a result of that program…unfortunately they are only partially resistant to the disease)
Breeding from scartch is pretty damn difficult, you need to take two seeded parents…make them have plant sex…and try and get a seedless, tasty, easily transported, good looking variety out the other end.
(There’s other more complicated ways of breeding, but it would be too difficult to explain here)
This is a try scary reality but it makes sense. I am surprised to hear that we have only one cultivar. My mum grew up in Brazil in the 50s and there were tons of varieties of bananas then – what happened?
Maybe someone could freeze-dry tons of bananas now for future use. Or maybe Monsanto has a solution, since they have patented most seeds on earth? In any case, I eat one banana a day and the thought of losing it makes me very worried.