Panama disease in bananas: how to recognise Fusarium wilt and limit it

On 27 March 2026 the Bangladeshi news site Jagonews24 published a guide by Samiran Biswas, an agriculture and environment specialist, on Panama disease, a fungal wilt of bananas. He described how the disease develops, how to recognise it in the field and what farmers can do about it, and his central message was that prevention matters most because the disease is difficult to control once it is in the soil. This report retells his advice and checks it against the work of banana researchers and of Bangladesh's own agricultural bodies, as that work stood when the article appeared.

Biswas began with the place of the banana in Bangladesh. He wrote that bananas are grown in almost every country and are available all year round, and that in Bangladesh the crop covers about 40,000 hectares and yields about seven lakh tonnes of fruit a year, around 42 per cent of the country's fruit. In his view, weaknesses in production, quality and processing keep Bangladesh from the export earnings that many other countries make from bananas, so farmers grow the crop mainly for the home market, and many of them miss the profits they expect because they lack knowledge of scientific cultivation. That, he wrote, is why growers need to understand Panama disease and the steps that limit it.

Official estimates of the banana crop differ from one agency to another, depending on what is measured, and the writer's figures are best read alongside them. The Bangladesh Bureau of Statistics (BBS) put the output of ripe bananas at 862,692 tonnes in fiscal 2024-25, up from 813,560 tonnes the year before, as The Financial Express reported on 23 December 2025. The Department of Agricultural Extension (DAE) works with a much larger total. Its data, reported by The Daily Star on 14 February 2026, show banana output rising from 15 lakh tonnes to 25 lakh tonnes over the period the paper reviewed, while mango output nearly doubled from 15 lakh tonnes in fiscal 2012-13 to nearly 27 lakh tonnes in fiscal 2024-25. On these DAE figures, mango rather than banana is the largest fruit crop.

The same DAE data show national fruit production rising from 1.03 crore tonnes in fiscal 2008-09 to 1.51 crore tonnes in fiscal 2024-25, even though the land devoted to fruit shrank from 9.35 lakh hectares to 7.79 lakh hectares over the period. The Daily Star credited much of that growth to a ten-year DAE scheme, the Year-Round Fruit Production for Nutrition Improvement Project, which ran from 2015 to 2025 with the aim of making fruit available throughout the year rather than in short seasons. Older reference figures show how long the banana has been a major crop: Banglapedia, the national encyclopedia of Bangladesh, records a harvest of 9,09,060 tonnes from 1,38,360 acres in 2005-06, and FAO statistics cited by the banana research network ProMusa put the area at 50,000 hectares and production at 774,000 tonnes in 2013.

Banglapedia notes that the banana grows almost everywhere in the country throughout the year and names Rangamati, Barisal, Rangpur, Dinajpur, Noakhali, Faridpur and Khulna as the principal growing areas. ProMusa's country profile lists Bogra, Narsingdi, Rangpur, Natore, Pabna, Noakhali, Faridpur and Khulna as the main districts of cultivation, records wild-growing bananas in Sylhet, Moulvibazar, Netrokona, Rangamati, Khagrachhari and Bandarban, and observes that banana plants are found in most rural homesteads. Among the types Banglapedia lists are Sagar kala, the cooking banana Kancha kala, the seeded Aita kala and the popular local varieties Chanpa, Sabri, Singapuri and Mahersagar, along with the hill banana Musa textilis, valued for its fibre. The fruit is eaten both as a vegetable and as a dessert, and the encyclopedia also records banana powder used in baby food, chocolate and biscuits, peel ash used in soap and the stem as a source of edible starch.

Biswas described Panama disease as a serious fungal disease, known in English as Fusarium wilt of banana, caused by the fungus Fusarium oxysporum and spread through the soil. Plant pathologists name the agent more precisely as Fusarium oxysporum f. sp. cubense, usually shortened to Foc, the form of the fungus that attacks bananas. Banglapedia calls it "a widespread and devastating disease in Bangladesh and other banana growing countries of the world".

The fungus lives in the soil and enters the plant through its roots. A review of the disease by Miguel Dita and colleagues, published in Frontiers in Plant Science in October 2018, explains that it usually gets in through the fine secondary or tertiary feeder roots rather than the main roots. ProMusa describes how it then colonises the xylem, the vessels that carry water up the plant; Banglapedia adds that the fungus blocks the vascular system so that the plant wilts, and that its entry is helped by the burrowing nematode Radopholus similis, which punctures the roots. The fruit itself shows no symptoms, according to ProMusa.

The disease has a long history. ProMusa calls it the first disease of bananas to spread around the world, which it did in the first half of the twentieth century. It probably originated in Southeast Asia; the first recorded case was in 1874 at Eagle Farm near Brisbane in Australia, and it was reported from Panama, which gave it its common name, in 1890 and from Costa Rica within a decade. Outbreaks followed in Suriname in 1906, Cuba in 1908, Trinidad in 1909, Jamaica in 1911, Honduras in 1916 and Guatemala in 1919. At that time the export trade rested on the variety Gros Michel, which proved highly susceptible. Resistant varieties were identified as early as 1910, but the industry switched to Cavendish bananas only in the late 1950s.

Scientists group the fungus into races according to the bananas it attacks. ProMusa explains that race 1 is found throughout the tropics and attacks Gros Michel, Silk, Pome and Pisang Awak types, while plantains and the East African highland bananas are generally resistant to it. Race 2 cut back the cultivation of Bluggoe, a cooking banana, especially in Latin America. Subtropical race 4 causes disease only when other predisposing factors are present, but tropical race 4, known as TR4, needs no such help and attacks Cavendish. The Dita review notes that Cavendish resistance to race 1 held for about 50 years, and that Cavendish bananas are the source of 99 per cent of banana exports.

Biswas listed the conditions under which the disease takes hold. It is likely to return the next year if the previous crop was infected or if planting material was taken from diseased plants. It also appears when suckers are planted too young, when the soil drains poorly, when weeds and grass are heavy and when the crop does not get regular intercultural care.

The research literature explains why infected planting material matters so much. ProMusa warns that suckers and rhizomes can carry the fungus without showing any sign of it, and that an infected sucker may show no symptoms until it is about four months old. The Dita review explains that the fungus forms thick-walled resting spores, called chlamydospores, once it has invaded the plant and before any outward symptoms appear; these spores resist drying and may survive in the soil for more than 20 years. The same review notes that weeds can carry the fungus without symptoms and act as a reservoir.

Spores also travel with soil and water. According to ProMusa, infested soil is moved on vehicles, tools and shoes and in potting media, animals may carry spores, and surface run-off and irrigation water can carry them from field to field; pumping contaminated water contributed to the spread of tropical race 4 in China. The Dita review adds rain splash and flooding, and names contaminated substrates and compost as further risks.

Soil conditions influence how badly a field is affected. The Dita review reports that well-drained, aerated soils are generally assumed to reduce Fusarium wilt while compacted soils may favour it, that lower soil pH and ammonium-based nitrogen fertilisers are associated with more disease, that low soil phosphorus has been linked to higher incidence, and that the burrowing nematode increased the disease in greenhouse studies. ProMusa notes that some soils suppress the disease, for reasons that are not well understood, and the review links such suppressive soils with more diverse communities of soil microbes.

Biswas described the signs farmers should look for:

• Yellow spots appear on the older leaves, and each older leaf gradually turns yellow all over.
• The edges of the leaves split, and the leaf stalks split.
• The leaf blades droop and dry out.
• Within two or three days all the leaves hang down, except the central heart leaf.
• The base of the pseudostem splits lengthwise near ground level.
• Infected plants produce an abnormal inflorescence.
• Inside, the infected plant and its rhizome look blackish.

ProMusa's description matches his. The older leaves yellow and wilt first, starting at the margins, and the yellowing moves on to younger leaves; leaves may collapse at the stalk and hang down around the pseudostem, the base of the pseudostem may split, and new leaves may have irregular pale margins or be distorted. Inside, the water-conducting tissue changes colour from pale yellow in the early stages to dark red or almost black later, first in the feeder roots and then in the rhizome and pseudostem. The Dita review adds that under natural conditions the disease is mostly noticed at flowering, though highly susceptible varieties facing heavy infection can show symptoms as early as three months after planting.

Other diseases can look similar. ProMusa notes that Fusarium wilt can be confused with Xanthomonas wilt and with Moko disease, and Banglapedia warns that bacterial wilt of banana, caused by Pseudomonas solanacearum, shows symptoms similar in some respects to those of Panama disease: it begins with a yellowish colour in the inner leaf blade close to the stalk, after which the inner leaves wilt. Because the treatment of each disease differs, a farmer who suspects Panama disease would do well to have the plants examined by the upazila agriculture office before acting.

Biswas's article did not discuss the races of the fungus, but by March 2026 tropical race 4 was the strain that worried banana scientists most. ProMusa records that it was isolated in Taiwan in the late 1980s, where the banana area fell from about 50,000 hectares in the 1960s to about 6,000 hectares by the early 2000s. It reached Indonesia and Malaysia in the early 1990s, destroying new export plantations within a few years, and a 2006 survey reported about 6,700 hectares severely affected in Guangdong, China. Jordan reported it in 2013, the first official report outside the Southeast Asia and Pacific region, and Mozambique the same year, in an export plantation. It was confirmed in August 2019 on 175 hectares in La Guajira, Colombia, the first report in Latin America, and in Peru in 2021.

The strain had also come close to Bangladesh. According to ProMusa's tropical race 4 page, Pakistan reported it in 2015 after symptoms were first seen in 2012; India reported it officially in 2018, based on isolates collected in Uttar Pradesh in 2017, after wilting had been seen in Bihar in 2015; Myanmar confirmed it in 2018; and Laos and Vietnam reported it in 2017. That page, last revised in March 2022, does not list Bangladesh, and none of the sources consulted for this report carried an official statement on tropical race 4 in Bangladesh as of March 2026.

ProMusa calls the capacity of the strain to survive indefinitely in the soil one of the main reasons it is considered a major threat. The Food and Agriculture Organization of the United Nations (FAO), which notes that bananas and plantains are grown in more than 135 countries, set up a TR4 Task Force under its World Banana Forum in 2013. ProMusa sets out the measures recommended to countries: designating tropical race 4 as a quarantine pest, monitoring to detect any incursion early, and regulations that allow the national plant protection organisation to inspect farms, collect samples and enforce the destruction of plants. On farms, it names the exclusion of all non-essential visitors, vehicles and planting material from outside as the first line of defence, with footwear change points and the washing down of vehicles with disinfectants.

Bangladeshi growers had already seen what the disease can do. On 5 March 2024 The Financial Express reported from Pabna that a banana disease had spread widely in Ishwardi upazila. The upazila agriculture office told the paper that 1,840 hectares were under banana that season, 1,800 of them in Laxmikunda union, and the affected villages included Dadapur, Kamalpur, Kaikunda, Charkurulia and Shantinagar. Some farmers said 60 to 70 per cent of their plants had been killed or damaged. The main varieties grown there were Mehersagar and Amritsagar. Farmers told the paper they had repeatedly contacted agriculture officials without receiving effective help; officials said they had advised farmers as many times as possible.

The advice reported then followed the same lines as Biswas's guide. The deputy director of the DAE in Pabna said infected plants should be uprooted or burnt, because piling them up spreads the fungus, and that farmers should plant healthy, clean banana plants. The Ishwardi agriculture office advised that banana growing in the affected area should stop for two to three years while other crops were grown, and that adding lime could help keep plants free of the disease. The chief scientific officer and head of the pathology department at the Bangladesh Sugarcrop Research Institute (BSRI) in Ishwardi identified the disease as Panama disease, or Fusarium wilt, caused by Fusarium oxysporum, and said there was no remedy and that no resistant banana variety had yet been developed.

For what he called organic management, Biswas advised farmers to take suckers only from disease-free fields, to remove diseased plants from the field and burn them, to use disease-resistant varieties, to change crops after two or three years and to apply lime to raise the soil pH. He stressed that once the disease spreads in a field it is difficult to control, so prevention is the most important measure.

Research supports each of these steps, with some detail. On varieties, ProMusa says replacing susceptible varieties with resistant ones is the best-adapted approach for continued production in infested soil; the FHIA hybrids resist races 1 and 4, and Giant Cavendish tissue-culture variants developed by the Taiwan Banana Research Institute, known as GCTCV, show varying resistance to tropical race 4. On planting material, ProMusa says certified tissue-culture plantlets should be free of the fungus; the Dita review recommends them to reduce risk but cautions that they can be more susceptible than conventional suckers, possibly because they lose beneficial microbes during culture.

On rotation, the Dita review reports that growing crops such as cassava, pineapple or Chinese leek reduced the incidence of the disease in some studies, and that a pinto peanut cover crop reduced its intensity by about 20 per cent. On sanitation, it describes the destruction of infected plants as a key starting point. On lime, the review advises that soil be analysed first and the pH and nutrients corrected accordingly, recommending a soil pH of about 5.6 to 6, and it reports one study in which calcium carbonate, calcium hydroxide and calcium sulphate reduced the germination of the fungus's resting spores and the severity of the disease without changing the soil pH. None of the sources gives a general liming rate, which depends on the soil, so the amount is a question for a soil test and the local agriculture office.

Farm hygiene completes the picture. ProMusa's guidance for keeping the disease out of a farm, or containing it, includes restricting who and what enters, changing or cleaning footwear, washing down vehicles, isolating infested areas and using ground covers and grassed inter-rows to reduce soil erosion, which carries the fungus.

Biswas also set out a chemical programme. He advised dipping planting material in a carbendazim solution before planting, treating the soil every two months from six months after planting, soaking planting pits with a formalin solution and planting 10 to 12 days later, and spraying a carbendazim-group fungicide on the base of the plant and the whole plant at intervals of seven to ten days, and he gave a dose for each step.

The international evidence on chemicals is cautious. ProMusa states that fungicides cannot control the disease and that fumigants cannot eradicate it from the soil. The Dita review reports that some fungicides have been effective in the laboratory and in greenhouses but that their effect in the field has yet to be validated, and that no single biological product can be recommended for widespread use against the disease. The BSRI pathologist quoted in 2024 said there was no remedy. As none of the government or research bodies consulted for this report gives doses for these treatments against Panama disease, this report does not reproduce the writer's doses. Farmers should consult the upazila agriculture officer before using any fungicide or soil disinfectant, and use only products registered for the purpose.

Biswas closed with safety advice that applies to any pesticide: always wear protective clothing when spraying, and follow the instructions on the label, including the dose, the time of application and the interval that must pass between the last application and the harvest.

Photo: The Roving Rokibul / Wikimedia Commons (CC BY-SA 4.0)

Sources: Jagonews24, ProMusa, Frontiers in Plant Science (Dita et al., 2018), Banglapedia, The Financial Express, The Daily Star, Food and Agriculture Organization of the United Nations (FAO)