What is Panama disease? Are bananas at risk?

The disease and conditions regarding its spread show that depending on monoculture crops is not sustainable for our food and nutritional security

Published: Thursday 16 July 2020

As human beings, we are always most worried about diseases that affect humans, especially the incurable ones. But what about diseases that affect plants and diseases that threaten our food security? Panama disease is one such problem, that is destroying banana plantations, not just across the world but also in India. 

Now to put this in perspective, we need to understand that bananas are the most consumed fruit in the world. In 2017, the average per capita consumption of fruits globally was 25.57 kilograms (kg) and bananas contributed nearly 40 per cent to this.
An average person in India consumes around 19 kg of banana every year. In the Philippines, it is over 21 kg. The US Food and Drug Administration says that a medium-sized banana can provide 110 calories, along with 450 milligram or 13 per cent of your daily potassium and 15 per cent of your daily Vitamin C requirements. 
The Food and Agriculture Organization (FAO) says that in countries where bananas are grown, they provide almost 25 per cent of the daily calories in rural areas. Therefore, this fruit is very important for our food and nutritional security.
And this connection does not just end with food. The banana plant also has very strong social and economic relevance to communities in South and Southeast Asia, Latin America and Africa.

Panama disease is caused by a fungus. One of its strains, called Tropical Race 4 or TR4, is creating the maximum havoc, threatening almost 80 per cent of the global banana production. The disease is so deadly that sometimes it is referred to as ‘banana cancer’.

The fungus resides below the ground and infects the plant through its roots. The infection then stops water and essential nutrients from being transported to the rest of the plant. The leaves begin to wilt and the stem of the plant starts turning dark brownish before the plant dies.

If one plant gets it, then it is most likely that an entire plantation can be wiped out. Now, if that sounds scary, what is scarier is the fact there is absolutely nothing, no medicine, no fungicide that can cure this disease.

Till the 1950s, there was just one banana variety called ‘Gros Michel’ or the ‘Big Mike’ that dominated international banana trade. Big Mike was known for its sweet taste. But what made this banana the export favorite was its thick peel which prevented bruising of the fruit when transported over long distances. And it also grew in thick bunches, again making it easier to transport.  

But there was one problem and a big problem that became its Achilles heel. This was its susceptibility to the Panama disease. This disease destroyed almost all the Gros Michel or the Big Mike plantations. 

So much so, that the banana industry had to replace the Gros Mitchel with another variety, a banana which was inferior in taste and less sweet called Cavendish. Today, almost all exported bananas belong to the Cavendish variety. 

But after 70 years or so the story has been repeated. And this time, the Panama disease has struck the Cavendish variety of bananas and is threatening to wipe it off the planet.

What makes these banana plants so vulnerable to the Panama disease? The answer lies in how they are grown. The quest of the banana industry has always been to grow beautiful and uniformly yellow bananas — bananas, without those ugly black or brown spots — bananas that look good on the supermarket shelves.

There are over 1,000 edible varieties of bananas, some of which are far sweeter and nutritious than the Cavendish variety. But they are ignored by the banana industry, the supermarkets and the consumers because of excuses such as — they are not attractive enough or they are hard to eat because they have seeds — and so on and so forth   

Now, because Cavendish is the most traded or commercially important banana, every fruit should look and taste the same. And this could only be done if all the plants came from one mother plant. So each Cavendish banana plant is a clone of all the other cavendish banana plants around the world.

You will never find seeds in these bananas. And they are propagated only through their rootstalk calle ‘rhizomes’ or shoots called ‘suckers’. That makes them genetically identical, carbon copies of one another. But this also means that they have the same amount of vulnerability to pests and diseases.

That is the reason why Gros Michel went out in the first place. They were all clones of one mother plant. Cavendish was once immune to the Panama Disease and that was the reason why the banana corporations lapped it up. 

Today, almost half of the bananas produced on the planet belongs to the Cavendish variety. But then, the Panama disease mutated and now threatens to wipe out all the Cavendish banana plants.

The Panama disease on Cavendish bananas was first witnessed in Indonesia and Malaysia in the early 1990s. It then spread to Southeast Asia and China. According to FAO, the disease has now spread to over 17 countries and has reached Latin America, the region from where the strain that infected Gros Michel emerged.  

Should India be worried about the disease? Yes, absolutely, because India is the largest producer of bananas in the world and this disease has found its way into the country. India produces close to 30 million tonnes of banana every year. 

And what is worrisome is the fact that almost 55 per cent of the commercial banana plantation and 65 per cent of banana production in India comes from these Cavendish clones like Grand Naine, Robusta, Bhusaval, Basrai, and Shrimanth.

While there is still no data on the extent of the damage in India, media reports suggest that banana plantations in at least four states — Bihar, Gujarat, Madhya Pradesh and Uttar Pradesh — have been badly affected by this disease. All these are areas where the Cavendish variety is grown.

So, is the most popular fruit in the world slowly inching towards extinction? It is too early to say this, but there are lessons to be learned from this disease outbreak. Depending on one variety and depending on monoculture crops is not sustainable for our food and nutritional security.

But the good news is that India also has about 20 native varieties of bananas which are grown commercially and many more wild species of bananas. Some of these may not be as good looking or seedless, but they sure pack a punch when it comes to taste and nutrition. It’s time we try them.

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