The global banana industry is facing a new major threat. On the 8th August, the Colombian Agricultural Institute announced that it has confirmed the presence of a strain of Fusarium oxysporum f.sp. cubense, known as Tropical Race 4 (TR4) in the northern region of the country. Since then the Colombian government has issued a national state of emergency, destroying crops and quarantining plantations in an attempt to postpone the spread of the fungus until a suitable preventative plan can be implemented.
TR4 has devastated the banana industry throughout southeast Asia for over 30 years since its initial discovery in 1989 in Taiwan. Since then it has been identified across Lebanon, Israel, India and Australia. Until now, Latin America, the global hub for banana production and exportation, has avoided the fungal pathogen commonly referred to as Panama disease.
Latin America has seen a similar incident in the past, with devastating results. Prior to the 1950s, the Gros Michel variety of banana was the primary export banana. However, the introduction and resulting spread of alternate strain of Fusarium fungus, TR1, almost entirely wiped out the variety from the region. This is when the Cavendish banana, which is the variety of choice for 99% of banana exports due to its resistance to the Fusarium strain which claimed the Gros Michel, took over as the leading banana crop. The presence of TR4 within Latin America now threatens the banana industry again, as Cavendish cultivars are not resistant to this strain of Fusarium.
“What we’re seeing is an almost apocalyptic scenario in which we’ll probably lose Cavendish as well,” says Sarah Gurr, Exeter University’s chair in food security.
The TR4 strain is found in soil and can lay dormant for years before infecting banana crops through the root systems, resulting in the damage of water and nutrient pathways within the plants thus leading to starvation and death.
Symptoms of TR4 infection in bananas include yellowing of plant leaves and stems, rotting of internal tissue, necrosis of plant parts and in severe cases, plant death (© David Jones, CABI and Francis Nduati)
TR4 is commonly transported via vehicle transportation, the clothing of plantation staff and from replanting of banana crops in different plantations. Enforcing the disinfection of transport vehicles travelling in and out of plantations, clothing and regulating the movement of crops between plantations are all actionable attempts to reduce the spread of the pathogen, however no country has been able to contain TR4.
“Governments from Latin America are working to establish a contingency plan. The major focus now is how to efficiently control TR4. The idea is to work with governments, the private sector, academic organisations and agricultural communities in the development and implementation of such strategies,” said Dr. Yelitza Colmenarez, Country Director for Brazil at CABI and lead organiser for crop pest and disease prevention programmes across South America.
Neighbouring countries are also taking-action in anticipation of the spread of TR4 across country borders. Fernando Araya, director of Costa Rica’s public phytosanitary department, said that the TR4 strain has been a latent threat within the region for years due to its standing in the global banana market, with the country seeking preventative measures to protect its banana sector to reduce the impact if introduction of the pathogen does occur.
In the hopes of providing effecting preventative tools for TR4, cross breeding programmes are being evaluated. As it may be possible to cross-breed with other banana varieties to produce TR4-resistant crops which are still suitable for consumer markets. However, such programmes take time, and it is feared that by the time such a variety can be produced implemented into the banana growing sector, the TR4 strain will have already decimated the industry throughout the region.
Until such a solution can be implemented that will prevent the further spread of the pathogen or even reduce it, the only actionable outcome for Colombia and the entire region is to continue enforcing phytosanitary regulations within banana plantations.
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