There’s no cure for a fungal disease that could potentially wipe out much of global banana production. Widespread adoption of cement paths, disinfection stations, and production strategies could net 3–4 USD of benefits for each dollar invested in Colombia.

Hundreds of millions of dollars in banana exports from Colombia are at risk due to a fungal disease best known as Tropical Race 4 (TR4). First detected in Asia in the 1990s, the Fusarium fungus that causes the disease arrived in Colombia in 2019, completing its inevitable global spread to South America, the last major banana production continent that remained TR4-free.

Researchers are confident a solution will be found but until then, slowing the spread is the only effective strategy.

The good news is that simple, effective measures are already happening in Colombia. These include building cement paths between banana plots, fencing them, and installing disinfectant stations at farm entry points. Measures like this are worth the investment.

Researchers at the Alliance Bioversity International and CIAT found banana producers can expect a 3–4 USD return per dollar invested.

“The solutions are not extremely technical, they just require money and awareness,” said Thea Ritter, an Alliance researcher. “We found the potential benefits are very large. We urge industry and the government to continue making the needed investments and accelerate ongoing efforts to educate producers and communities about TR4. If it spreads more, it will devastate local and national economies.”

The research was published Oct. 30 in PLOS ONE, in likely the first socioeconomic study of its kind in the Americas.

Ritter and colleagues researched TR4 in the Colombian departments of Antioquia and Magdalena, two large export-oriented banana production areas, because they found no farm-level research on TR4 in the country.

Results found considerable, little-understood local and cultural impacts of the TR4 threat. These intangible details of the study paint a broader picture of what banana crop decimation could mean for the thousands of livelihoods that depend on the industry.

Unstoppable race

When TR4 infects soils, for all practical purposes, it is there to stay. At least four decades are needed for it to go away. Almost all bananas planted in infected soils will die. This includes the Cavendish, the world’s most popular fruit, and many plantains that are staples of tropical diets.

Some 80% of all bananas planted globally are susceptible to TR4. The disease also affects tomatoes, sweet potatoes, legumes and curcubits (the gourd family), limiting alternatives for farmers who may have to switch cultivars to keep producing food.

“Even if you plant crops like rice that are not susceptible to TR4, the risk of transmission remains because the soils remain infected,” said Diego Álvarez, a co-author and Alliance researcher.

TR4 spreads in several controllable ways. One primary driver is simply dirty boots—stepping on TR4-infected soils and then walking to TR4-free soils is one easy way to spread the disease. Disinfectant stations, fences and cement paths effectively reduce this risk.

Other transmission methods require a bit more effort, including changes in production practices. These include disposing of infected bananas in waterways, as TR4 can spread through water. Soil erosion, containable by cement paths and effective drainage systems, is also a TR4 superspreader.

Additionally, trucks that transport bananas are not routinely disinfected, suggesting that TR4 awareness and investment is necessary beyond producers.

Ritter points to a common propagation practice as one of the biggest threats—the use of corms (the “baby” banana plants that grow at the base of banana trees) to sow new plots. Farmers need to either effectively screen corms for TR4 before transplanting them, or rely on the more costly, certified disease-free plants.

“Awareness of the disease is high; we found that 99% of the farmers we interviewed knew about it and the associated threats,” Ritter said. “But there is much lower awareness of the threat posed by using corms. Farmer training—and investment strategies—need a greater focus on this issue for more effective containment.”

Colombia in the race

Colombia is fortunate because its government, banana industry and grower cooperatives are organized, aware of the TR4 threat, and taking action, researchers said.

“We have a good environment in Colombia’s banana sector to slow the transmission of TR4,” said Leslie Estefany Mosquera, a co-author and Alliance researcher. “But we need more awareness and commitment from policymakers to increase the required biosecurity measures. More policymakers need to be made aware of the urgency of the issue and to dedicate the resources needed.”

Challenges to providing them with enough information, however, remain. Because TR4 could literally alter Colombia’s agricultural landscape, not enough people close to the problem are willing to openly speak about it.

How TR4 impacts household livelihoods

Fusarium represents considerable losses for producers in Magdalena, where producers must group in cooperatives to sell their bananas abroad and production areas are not as large as in Antioquia.

Banana grower families in Magdalena would be directly affected by the presence of Fusarium through the loss of large portions of land that now cannot produce bananas for marketing, which reduces their income, affects their livelihoods and harms their food security.

In Colombia, finding a banana plant infected with Fusarium means losing 2.56 hectares of production, on average, due to the quarantine regulatory area established in this country. This, in a region where at least half of the producers have a production area of less than 3 hectares, leaves the average producer fearful of what could happen if the situation gets out of control and the plantations of several producers are affected.

Beyond Magdalena producers, other actors in the banana value chain in Colombia anticipate wide-ranging impacts from TR4. The disease is expected to cause a decline in banana production, reducing the availability of one of the country’s staple foods.

This reduction in production could increase prices and limit access to bananas, particularly affecting low-income households that rely on bananas as an affordable food source. The economic ripple effect extends to labor as well; with plantations potentially being abandoned or destroyed, job losses loom.

Many families that depend on plantation work for their livelihoods may experience a significant reduction in income, further straining their ability to secure food and meet basic needs.

Touching the intangibles

It’s hard to understate the importance of on-the-ground research of any major threat affecting farmers. National and regional studies effectively capture the big picture—such as modeling the spread of TR4 and the potentially massive hit that agricultural GDP will take if the disease spreads unchecked. But what of the people on the ground whose livelihoods, culture and communities are at existential risk?

Most farmers are willing to talk about TR4—anonymously and individually with researchers. But they are highly reluctant to report the detection of TR4 on their lands or communities. This is because TR4 scares away investors and farmers would see access to credit and other financial or technical support dry up.

The TR4 stigma may lead to under-reporting of the disease’s spread if systematic monitoring is not in place. It is also of little help that farmer cooperative leaders, who likely have deeper understanding of TR4 at wider scales, did not talk to researchers for this study.

“Policymakers should also address the disincentives around discussing TR4,” said Ritter. “We all need as much information as possible about where the disease is spreading and how it is impacting farmers to first, deploy mitigation strategies for effective containment and, second, to support farmers whose incomes could be destroyed by TR4.”

Researchers also identified major concerns that aren’t easily captured by cost-benefit-analysis or GDP projections. Bananas are deeply embedded in Colombian culture, as a staple food, a backbone of a farmer’s income, and national identity.

TR4 has the potential to disrupt traditional farming practices and community structures, which could lead to social upheaval, including the strong social ties and traditions built around banana-based livelihoods. Ultimately, traditional knowledge in communities related to banana harvesting and associated agricultural practices are at risk.

Ritter said, “We need to understand that many thousands of people’s lives, communities and cultures are threatened by TR4 and to take this seriously.”