Crystal Nelson
An aggressive fungal disease is threatening banana plantations worldwide. The banana disease TR4 hits the variety that accounts for 99 percent of all export bananas.
A fungal disease called Tropical Race (TR4) is threatening the Cavendish banana variety. So far there is no antidote.
Now the mushroom has also arrived in Costa Rica. The country has declared a phytosanitary state of emergency.
The fungus is harmless to humans, but deadly to the banana plant.
After apples, the banana is the most popular fruit in Germany: each of us consumes an average of twelve kilograms of the yellow fruit every year. Now the banana is in serious danger: a fungus has been spreading for several years, for which there is currently no antidote. Now the aggressive fungal disease Tropical Race 4 (TR4) has also reached the continent from which almost all bananas in our supermarkets come: Latin America.
Dangerous fungus: The banana is in danger
So far, the banana disease has mainly occurred in Asia and Africa, where it has destroyed entire plantations. In the meantime, however, scientists have also found TR4 in South America. They detected the pathogen on plantations in northeastern Colombia, and in Costa Rica this summer. The spread is so serious because South America is by far the most important growing area for bananas for the European market.
Will there soon be no more bananas?
“TR4 primarily affects the Cavendish banana variety,” explains the German Fruit Trade Association. “It is to be feared that in the foreseeable future there will no longer be any bananas of the Cavendish variety available for the German market.”
This is what makes the banana so sensitive
The banana disease is so dangerous because there is no alternative to the Cavendish banana: It is cultivated in monocultures and is the most important export banana worldwide, in Germany it has a market share of over 90 percent.
In addition, cultivated bananas are genetically identical clones, which makes them particularly susceptible to diseases. Cavendish bananas also do not produce seeds because banana seeds are large and hard and not very tasty. That is why bananas were bred, which do not propagate via seeds, but are obtained from seedlings. Each young plant is a clone of the old plant. This makes them attractive for large-scale cultivation – on the other hand, the almost identical plants are extremely susceptible to diseases.
Dangerous banana disease TR4
The sac fungus of the genus Fusarium infects the banana plant through the roots and slowly but surely causes it to die off. Infested areas have to be cleared and can no longer be used for banana cultivation because the fungus has the ability to survive in the soil for years.
How can the banana be saved?
There is no effective fungicide, and no alternative resistant banana variety ready to be grown on a large scale. Scientists are working flat out to find resistances in wild bananas and transfer them to the Cavendish banana. However, crossing the Cavendish banana with wild banana species is not so easy, since cultivated bananas do not reproduce through seeds. Researchers are currently working on genetic engineering techniques to breed bananas that are resistant to fungal and viral diseases.
After finding the TR4 pathogen, Colombia declared a national emergency and provided 18 million dollars to combat it. The government and plantation owners are now doing everything they can to prevent the disease from spreading further. Costa Rica has also declared a phytosanitary state of emergency.
Organic bananas are generally always the best choice – but with regard to TR4, reaching for organic goods is not helpful, the fungus affects organic fruits just as much as conventional ones.
The disease is harmless to humans
So far, there has been no sign of the banana epidemic in our supermarkets. Banana lovers in this country do not have to be afraid of TR4, the fungal disease is completely harmless to humans. However, if the South American banana plantations are gradually destroyed, this will also lead to rising banana prices in this country.
Much worse, however, is the fact that the exporting countries are losing important income from trading in the globally popular fruit, and a staple food that is important to the population may soon no longer be available.
Climate change is an additional threat to bananas
Not only the fungus threatens the future of the banana. Climate change could also affect the banana harvest in the future, researchers warn in the journal Nature Climate Change. From 2050, there could be massive crop losses, especially in India, Brazil and Colombia.
