Bananas in Peril

January 7th, 2011 | Simcha Weinstein | 1 Comment »

Bananas may be the world’s oldest cultivated crop. They were first grown in Southeast Asia as many as 10,000 years ago. Today, bananas account for a $4 billion-a-year worldwide export trade. The problem is that nearly all of these bananas are of a single variety – the Cavendish, which is now being attacked by a fungus called Tropical Race 4. There are legitimate concerns that this fungus could take down the entire banana crop, and it wouldn’t even be the first time this has happened.

Disaster struck in the mid-1950’s when another disease – Panama Disease – hit the Gros Michael banana – the commercial variety that was the predecessor to the Cavendish. The Gros Michael was a sweet banana (much sweeter than the Cavendish) and had a thick skin, that was much less prone to bruising during transport than the Cavendish variety. The Gros Michael was the variety of choice for export during the 1920’s – 1950’s and during that time made the Central American region the top banana producing area of the world.

Once Panama Disease hit, within a few years, the crop was devastated and this forced a move to the less flavorful, but more resistant, Cavendish fruit. This has been the reigning banana of commerce, but it is now threatened by the new Tropical Race 4 disease. The problem is not only with the disease itself, but also with how the bananas are raised. As Victoriano B. Guiam writes,

All of the Cavendish grown in the world are genetically identical, being but clones of the original plant. Genetic diversity is absent because the plants are multiplied through vegetative reproduction as sexual reproduction is not feasible. The lack of genetic variation is an assurance for the success of a marauding pathogen once it exploits the weakness of identical clones. The disease of one is the disease of all. Thus, in places where Foc Tropical Race 4 (TR4) has surfaced, the industry is once again confronted with the Gros Michael nightmare, according to Dr. Molina, who is also the coordinator of the Banana Asia and Pacific Network (BAPNET) and is intimately familiar with the threat.

The foci fungus is soil-borne and remains in an affected area for decades. According to Dr. Molina, it is efficiently spread through water and irrigation systems. It would be best to avoid the use of infected water or water that runs through affected areas. Infection of the plant is through injured roots of the banana plant. The fungus then invades the xylem vessels appearing as a reddish-brown discoloration and advances into the corm. Eventually the fungus affects the whole stem and above ground symptoms appear.

The Tropical Race 4 disease appears to be equally as potent as the Panama Disease. It first appeared in Malaysia and Indonesia, and has spread to northern Australia and South Africa. So far, it has not found it’s way to Latin America (which grows nearly all of the bananas for the U.S.), but many experts believe it’s only a matter of time. Currently, no known pesticide is effective against this disease. So what might be the impact of another banana devastation? According to writer Craig Canine, who has done some excellent reporting on this:

More is at stake than a healthy snack. While the banana is America’s No. 1 fruit (on average, each person in the United States gobbles more than 26 pounds of them a year, compared with 16 pounds of apples), bananas play a small role in the American diet. But for hundreds of millions of people in developing countries, bananas are a dietary staple—the least expensive source of nutritious calories. The banana ranks fourth after rice, wheat and corn among the world’s most economically important food crops. Of the nearly 80 million tons of bananas produced annually around the globe, less than 15 percent are exported to the United States, Europe and Japan. The rest are consumed locally. India and Brazil, the top two banana-producing countries, export almost none. Yet sub-Saharan Africa leaves both countries far behind in per capita consumption. A typical person in Uganda, Rwanda or Burundi consumes more than 550 pounds of bananas a year.

If there is a bright spot in all of this, it’s that there is a potential replacement for the Cavendish banana waiting in the wings. It’s name is Yangambi Km5. According to Canine’s reporting:

It yields abundantly, with big bunches and many fingers. It’s highly tolerant to many pests, and very male and female fertile, so it’s easy to cross with other varieties. But the peel is quite thin, so it’s not ideal for handling and shipping. They are working with it, developing crosses for a thicker skin and good fruit size. It’s a very promising candidate for improvement. The fruit was slightly shorter and stubbier than your average Cavendish. I took a bite. The flesh was creamy and sweet, though far from cloying. I detected hints of strawberry, vanilla and apple—perhaps even a dash of cinnamon. I like a good Cavendish as much as anyone, but this banana was in a different league. Yangambi Km5 has survived for centuries thanks to the care of subsistence farmers in the heart of Africa, and yet when I bit into it I imagined I was tasting the future.

Let’s hope he’s right, although it may take a while for Yangambi Km5 to become a household name.