You’ve probably heard of the Panama Papers, but how about Panama Disease? Remember the name, because it’s likely you’ll hear much more about it in the next few years.
Also called Fusarium wilt, Panama Disease is caused by a fungus and affects banana plants (as well as tomato, tobacco, sweet potato, and a variety of others). It’s spreading throughout the parts of the world where the Cavendish banana—the type you see in the supermarket—is grown. Asia, Africa, and parts of Australia are affected. It has not yet reached Latin America—the primary source of bananas imported to the US—but growers there are worried. Once established, the fungus can survive in the soil for decades.
This isn’t the world’s first go-round with Panama Disease, and for that matter Cavendish bananas are not the bananas your grandparents probably ate. In the 1950s the disease decimated another variety of banana called the Gros Michel, said to be much better tasting than the Cavendish. But the Cavendish was resistant to that strain of Panama Disease—and had other desirable attributes, such as surviving well during shipping—and so was adopted as a substitute. Now this cultivar, too, is under attack.
Nearly 1,000 varieties of bananas exist in the world; they come in many sizes, colors, and textures, including some we’d probably have trouble recognizing as cousins to the ones we eat on our breakfast cereal. So why do most of us know only the Cavendish? Because it’s easier and cheaper for growers to plant a single variety.
Monoculture farming is convenient in many ways. Cavendish bananas (the plant is actually an herb, not a fruit) are standardized and seedless, and they can be farmed very efficiently. But because most of the banana plants are now essentially clones, they have little resistance to parasites and disease, which can easily wipe out entire plantations.
The problem affects more than just bananas. Large-scale afforestation and reforestation projects are taking place throughout the world; planting trees can help prevent erosion and desertification, help to better manage water resources, and increase carbon sequestration. With the rapidly increasing number of wildfires, the rate of large-scale tree planting to minimize subsequent long-term soil erosion will only accelerate. Many such projects, though, simply plant a single variety of tree over a vast area, creating vulnerable monocultures. This seems to be a less-common mistake with other plants used for erosion control, where careful mixtures of plants—sometimes combinations of quick- and slow-growing or seasonal species—are frequently used. It’s disheartening, then, that the problem occurs in afforestation projects, whose impact, if all goes well, should last lifetimes.
Some countries spend more effort and planning upfront and create more disease-resistant forests. In Israel, for example, more than two-thirds of the forests have been planted where none existed before, with much of the work done by volunteers under the direction of the forest service. Trees of different species and ages are combined in a single area, with different mixes appropriate to each of the country’s three climate zones. It’s a model for other projects to follow, but it takes some work to get it right.
Meanwhile, big banana growers like Chiquita, hoping to salvage the $36 billion banana industry, are now experimenting with genetically modified versions of the Cavendish that appear to be resistant to Panama Disease. Another option, of course, would be to grow a mixture of different types of bananas—but that would require different harvesting, packaging, and shipping methods and would cost more.
Have you been involved with reforestation or afforestation projects in the US or elsewhere? How were the types of trees decided on, and how great a variety was planted?
Janice Kaspersen
Janice Kaspersen is the former editor of Erosion Control and Stormwater magazines.