Taipei: When the banana-killing Panama disease was detected in September 2025 in Ecuador, the world’s largest banana exporter, it sent chills through the global industry. The “Panama disease,” a destructive wilt caused by a fungus whose most aggressive strain is known as TR4, is particularly feared because it attacks the “Cavendish” banana variety, which accounts for roughly half of global production and more than 90 percent of banana exports. There is no known cure, and the TR4’s symptoms are usually not visible until after the fungus has established itself in the soil, when it is too late to take action, leading to worries that the Cavendish variety could one day become extinct. Taiwan, however, has managed to at least co-exist with the fungus since it first attacked nearly 60 years ago and recently cracked the code behind TR4 resistance that could give the world renewed hope that the fungus can be beaten.

According to Focus Taiwan, Taiwan’s banana plantations were first struck by TR4 in 1967, when infected banana plants were discovered in Pingtung County, said Su Yu-yen, a Taiwan Banana Research Institute (TBRI) assistant research fellow who has studied bananas for over 15 years. Infected banana plants usually show yellowing along the leaf edges before wilting, and the fruit becomes small, misshapen, and inedible, Su told CNA. Without knowing much about the disease, farmers cut down infected trees, disposed of them randomly, and replanted lateral buds from infected plants, unintentionally spreading the fungus further.

“Over 80 percent of banana farms [in Taiwan] are still infected with TR4 today,” Su said. To address the problem, the TBRI collected the lateral buds from banana trees that seemed less affected by the disease and cultivated new infected buds in labs to create thousands of small plantlets. Plantlets appearing to the naked eye to be disease resistant in the lab were then planted in contaminated soil to determine which, if any, could survive the fungus on the farm.

It was through that process that the first disease-resistant Giant Cavendish strain, the Taiwan Banana No. 1, was identified, and it was first planted for harvesting in 1992. Eventually, seven variants, including the Tai-Chiao No. 1 (80-90 percent resistant to TR4), No. 4, No. 5 (80 percent resistant to TR4), and No. 7, were identified as showing resistance while co-existing with Panama disease. In 2025, the TBRI successfully used the “Williams” banana variety, also vulnerable to the TR4 fungus, to create a new disease-resistant variant, with 70 percent resistance to Panama disease.