What Is Panama Disease? Fungus Could Wipe Out World’s Banana Supply

The humble banana is the U.S's favorite fruit, with an average American adult consuming 11.4 pounds of bananas per year.

This curvy, yellow fruit has a global appeal and half of the world’s banana exports went to the United States and the European market.

But, this handy fruit is facing a major crisis now. A fungal disease called the Panama Disease could cause this fruit to disappear in the next decade, leaving us with a banana-shaped yearning in our heart and stomach.

Panama Disease is a widely documented pathogen that affects the roots of banana plants. It is a type of Fusarium wilt that causes these plants to die and is caused by a fungal pathogen Fusarium oxysporum f. sp. cubense (Foc). The major problem here is that the pathogen is resistant to fungicide or any other form of pathogen killing chemicals currently used in agriculture and can survive in soil for 40 years.

This is not the first time bananas have been at risk. In the 1950s the same disease wiped out most bananas from the world. During that period most of the world consumed one type of banana known as the Gros Michel banana. When these bananas started showing signs of Panama disease, almost the entire global stock perished because nobody knew how to stop it. At least, not until they discovered the Cavendish banana.

The Cavendish variety was found to be resistant to this fungus. Once we figured this out, there was an explosion of Cavendish bananas in the 1980s. Farmers globally switched to these varieties seemingly overnight and our affair with this fruit continued without most of us realizing that what we loved so dearly was changing.

Bananas are reproduced asexually through replanting the plant's basal shoot that grows after the original plant has been cut down. This process makes most of the genetic material to be the same between two separate plants. The same happened with the Cavendish too.

Now, when the production spread to Indonesia, we found that the variation of the Panama Disease found in the soil there affected Cavendish too. It started killing off the new Cavendish variety faster than the older version of the Panama disease, inspiring panic and a new name called tropical race 4 (TR4).

Since they are similar genetically if one is affected, the other tend to be easily susceptible too. Lack of genetic variability caused the infamous Irish Potato Famine from 1845 to 1852 where the population of potatoes, a primary constituent of the Irish diet, was infected by a disease called Phytophthora infestans. Like the Cavendish, the Irish potato lumper crop lacked genetic diversity, which caused it to start dying out, which led to millions of deaths and mass migrations from Ireland.

It’s estimated that a million people died of starvation in Ireland alone, with another two million people emigrating out of desperation.

Now, scientists are trying to activate genes in the Cavendish that could counter this disease but research, testing and perfection can take years. The disease has already started spreading in many parts of Asia and is threatening the global banana population.

There are over 100 varieties of bananas in the world but 99 percent of the bananas consumed are of the Cavendish variety. An easy way out of this problem would be to identify other types of banana which are resistant and diversify the global produce. Introducing genetic diversity will ensure more resistance and an overall stability that bananas grown now lack.