The causal agent of the Tropical Race 4 of the Banana Fusarium wilt fungus Fusarium oxysporum f.sp. cubense, known throughout the industry as TR4 or Panama disease, is considered the biggest threat to bananas in Latin America and the Caribbean as well as in Asia, Australia, and Africa.
Fazil Dusunceli, an expert on TR4, working for the Food and Agriculture Organization of the United Nations (FAO), explains that, once the fungus is established in the soil, it stays there for decades and it is not possible to eradicate completely.
“Once it finds its way into a farm—entering through infected plant materials, infested soil particles on shoes, vehicles, etc.—if it is not contained in the initial incursion sites, it can spread further and cause significant damage to the banana production,” Dusunceli says. “It can cause 100 percent losses within a few years depending on the farm practices.”
That is noteworthy as bananas are the eighth most important food crop in the world and the fourth most important food crop among the world’s least-developed countries, according to FAOSTAT, the UN agency’s data-gathering and analysis service.
On a global scale, commercial productions are heavily dependent on the Cavendish variety, which is very susceptible to the TR4 fungus, making global banana production systems vulnerable to the threat. Plus, there is currently no known effective treatment to control the disease for Cavendish cultivars. Therefore, preventive measures are the only viable option.
“Theoretically, all banana producing countries are potentially a target for the disease, and global vigilance and cooperation among banana producers are key to fighting it,” Dusunceli says. “The slight advantage of this disease is that it is luckily not airborne and does not spread through winds or the fruits. So, if producing countries apply the necessary biosecurity measures properly, it is possible to contain TR4 in the first incursion spots and prevent its spread.”
The GlobalG.A.P., an active member of FAO’s World Banana Forum, developed a web tool that acts as a biosecurity add-on, setting out voluntary certification standards and procedures for good agricultural practices to help its members and farmers.
Dusunceli explains the add-on outlines the checklists for implementation of the farm biosecurity measures to ensure that the TR4 fungus does not enter and spread. This aims to assist farmers in proper implementation of the phytosanitary practices and actions needed to prevent entry and spread of the fungus into and out of the farms.
“This call for action is inclusive and all stakeholders in the banana value chain can sign in and establish commitments to prevent TR4,” Dusunceli says.
Farmers need to be on alert and plan their production lines and structures to prevent spread of the fungus. Steps they should take include following the principles of phytosanitary measures as outlined by the International Plant Protection Convention.
Some farmers in Southeast Asia have shown that certain measures and approaches to containing the disease—such as using new lands for production, moving into local cultivars and more tolerant clones combined with rotation and inoculum reduction practices—can help to sustain production and trade, hopefully enabling farmers to either maintain or quickly regain economic viability of their operations.
Dusunceli feels that, to help the producers, countries need to work on identifying the risks, creating awareness, and taking necessary measures at large. Long-term actions include:
- Developing and implementing national strategies and contingency plans
- Awareness at all levels, including technical officers, producers, and workers
- Assessment and strengthening legislation on regulations
- Running risk assessments, surveillance, and early warning systems
- Supporting seed systems to produce and use disease-free tissue culture–based planting materials
- Training technical officers, producers ,and farm workers in disease identification, prevention, and management under field conditions, and appropriate instructions to visitors
“All these actions need to be taken proactively before the introduction of the pathogen,” Dusunceli says. “There is also a great need for strengthening and supporting the international collaboration to help countries in their efforts to fight the spread of the disease.”