Fungal Threat Puts Reunion Banana Farmer's Livelihood at Risk

Gilbert Bafinal grows bananas on a plot in the Ravine des Cabris district of Reunion, and ninety percent of his income depends on that single crop. That concentration of risk has always been a fact of his working life. Now it has become a source of dread, as a fungal disease advances steadily across the Indian Ocean toward the French island territory. Tropical Race 4, known as TR4, has already devastated plantations in Mayotte, the Comoros Islands, and Madagascar. It has not yet reached Reunion's soil. But for Bafinal and farmers like him, the distance feels shorter every season. He grows Grande Naine bananas, a variety considered particularly vulnerable to TR4. The prospect of uprooting plants, switching cultivars, replanting, and then waiting several years to restore adequate production represents an economic catastrophe for families whose fields depend almost entirely on this crop. Bafinal has considered resistant varieties as a fallback, but a separate concern troubles him. "For the customer, what matters is taste," he said. "So changing variety, yes, but I fear the taste will no longer be there." Reunion's residents have experienced banana shortages before, mostly after cyclones, when prices have climbed above eight or ten euros per kilogram for months at a stretch. The establishment of TR4 in Reunion's soil would be categorically different. Certain plots could become permanently unusable for current varieties, forcing the island to rely increasingly on imports. Transportation costs would push prices upward at local markets, turning the banana from a daily staple into something closer to a luxury item. By contrast, the response taking shape on the island is collective and urgent. Eric Lucas, diversity officer at the Chamber of Agriculture of Reunion, has been direct about the stakes. "We have had suspicions and alerts, but no confirmed cases," he said. "The disease is very present in Mayotte, the Comoros, and Madagascar. It is alarming because people travel frequently and can bring the disease back." His message to travelers is unambiguous: the risk of transporting a cutting or plant is too great to take. TR4 is a fungus, not a virus. Dr. Isabelle Robène, a researcher at Cirad within the Mixed Research Unit for Plant Populations and Bioaggressors in Tropical Environments, explains how it works. "The fungus penetrates banana plants at the root system level, then progressively invades the plant's vascular vessels," she said. Leaves yellow, the plant withers, and it dies. What makes TR4 especially dangerous is its persistence. Once established in soil, it is extremely difficult, if not impossible, to eliminate. Its spores can survive indefinitely, and no chemical treatment can eradicate them. TR4 targets the Cavendish cultivar above all others. Cavendish represents more than forty percent of global banana production and approximately ninety-nine percent of worldwide exports. In the Indian Ocean region, the fungus was detected in Mozambique in 2013, in Mayotte in 2019, and in Grande Comore in 2023. Its progression across the region has accelerated, and agricultural authorities are watching closely. For Reunion's farming families, the risk of introduction often arrives through gestures that seem harmless: a cutting tucked into luggage, contaminated soil clinging to the soles of shoes. In 2025, Reunion's customs authorities recorded 157 instances of illegal plant product introductions. Roughly thirty percent originated from mainland France, twenty-five percent from Madagascar, and nearly twenty percent from Mayotte, including products arriving from the Comoros via that island. Customs agents have received specific instructions regarding TR4 risk, and flights from Mayotte now face enhanced monitoring. The legal framework is already in place. A prefectural order dated April 24, 2017 prohibits the introduction of fresh plant material without the required phytosanitary procedures, whether by mail or in baggage. Violators face up to three years imprisonment and fines equivalent to twice the value of seized goods. On the ground, approximately fifty sentinel plots are monitored through an official system led by the Agricultural and Fisheries Department and implemented by the Departmental Federation of Plant Protection Groups. Cirad has developed a rapid detection test usable directly in the field, without heavy laboratory equipment. Any positive result must be confirmed by the National Food Safety, Environment and Labor Agency (Anses) Reunion. Robène stresses the need to strengthen communication and awareness among travelers arriving from affected zones, and points to biosecurity measures such as disinfecting shoe soles after visiting contaminated regions. Lucas keeps his message to the general public simple: Reunion's varieties are excellent, and there is no reason to seek novelty elsewhere and risk importing disease along with it. No TR4 outbreak has been confirmed on the island. Every measure currently in place is designed to keep that statement true, so that producers like Bafinal can continue working their plots and bananas remain affordable on Reunion's markets. Whether collective vigilance will hold as travel and trade between Indian Ocean islands grows more frequent is a question the island's farmers are living with every day.