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The East African : Jun 14th 2015
The EastAfrican OUTLOOK JUNE 13-19,2015 D E VE LO PME N T New strain of banana fungus threatens world harvests, says UN TR4 appea≥ed this yea≥ in Aust≥alia, afte≥ sp≥eading to Asia and Af≥ica By PHOEBE SEDGMAN Washington Post-Bloomberg S ix decades after a bananakilling fungus all but wiped out plantations across Latin America, a new strain threatens to destroy global harvests. A type of Fusarium wilt ap- peared this year in Australia’s main banana-growing state after spreading to Asia and Africa. While the fungus has been around since the 1990s and has yet to affect top exporter Ecuador, Fresh Del Monte Produce called it a potential “big nightmare.” The United Nations says the disease threatens supply, and Latin American growers are taking steps to limit the risk. The industry survived the demise of the top-selling Gros Michel banana in the 1950s by switching to a different variety, called the Cavendish. But this time, there’s no ready substitute. Americans now eat bananas almost as much as apples and oranges combined, and are the biggest buyers in an export market valued at more than $7 billion. “We don’t have anything that can replace the Cavendish,” said Gert Kema, a plant research leader at Wageningen University in the Netherlands, who studies banana diseases. Part of the problem is the way the market evolved more than a century ago, relying on a single breed rather than several varieties. In 1870, the founder of what became Chiquita Brands International imported 160 bunches of bananas from Jamaica into the US that he sold at a profit, kicking off an American industry built around perishable tropical fruit from overseas that competes with cheap, locally grown apples. While there are more than 1,000 types of bananas, many are either inedible or consumed where they are grown. To make money on exports, growers had to rely on a single variety to ensure uniformity and keep production costs low. Until the 1960s, that was the Gros Michel, which all but disappeared after a decadeslong spread of what came to be known as Panama disease. “The monoculture, the reli- ance on a single banana breed that makes all this possible — that makes the low margins If we carry out controls at a regional level, then it will be very difficult for TR4 to spread.” Eduardo Ledesma, director, Banana Exporters Association in Ecuador Banana traders in Embu County, eastern Kenya. Researchers say Panama disease Tropical Race 4 will continue to spread as long as susceptible banana varieties are being grown. Picture: File work — also makes that fruit very susceptible to disruption,” said Dan Koeppel, who has travelled to 30 countries to sample varieties and wrote Banana: The Fate of the Fruit That Changed the World. “The biggest problem is disease.” A lack of plant diversity isn’t unique to bananas. After a history in which more than 7,000 species were cultivated for human consumption, today just four crops — rice, wheat, corn and potatoes — are responsible for more than 60 per cent of human energy intake, the UN’s Food and Agriculture Organisation estimates. Losing breeds can be costly. When Gros Michel was killed off, the Cavendish proved immune to the fungus strain, though the bananas were smaller, less hardy and not as tasty, Koeppel said by phone from Los Angeles. It allowed the industry to recover, but the new variety required shipping in smaller boxes rather than big containers, he said. It took years to convert operations from farms to retailers. Still, demand took off. Glo- bal banana production surged five-fold from 1961, with increases in India and China, which together account for 37 per cent of output, FAO data show. The US and European Union are the top importers, while Ecuador and the Philippines are the top shippers. The FAO estimates bananas provide income or food to about 400 million people worldwide. Over the past two decades, a new strain of Fusarium wilt — called Panama disease Trop- THE ‘BIG NIGHTMARE’ Panama disease Tropical Race 4, a new strain of Fusarium wilt threatens the Cavendish, a banana variety introduced in the 1950s to substitute the top selling Gros Michel banana, which had been hit by disease. TR4 enters the plant’s roots and spreads, invading vascular tissue. The first symptom is ical Race 4 — emerged to threaten the Cavendish, including in the Philippines and China and in parts of Africa. This year, it was found in Queensland state, where more than 90 per cent of Australia’s A$600 million ($467 million) crop is grown. Growers from across Latin America met in March to create a regional defence effort and will gather again in September or October, said Eduardo Ledesma, director of the Banana Exporters’ Association in Ecuador. No specific regional measures are in place, though Ecuador growers have asked the government to fumigate all containers, he said. “If we carry out these controls at a regional level, then it will be very difficult for it to spread,” Ledesma said from Guayaquil, Ecuador. “Not impossible, because nothing is impossible in life, but very difficult.” The strain is easily spread by people — through dirt on shoes, tires on trucks, shipping containers or other infected equipment — as well as through rain, floods and run-off water. Because most of the world’s Cavendish bananas are clones, a disease affecting one plant affects irregular yellowing of older leaves, which later turn brown and dry out. The disease poses no threat to humans. The capacity of TR4 to survive decades in the soil, along with its lethal impact and wide host range, are among the main reasons it was recently ranked as the greatest threat to banana production4. them all, the FAO says. In Queensland, where resi- dents are affectionately known as banana-benders, a farm in Tully, over 1,280km north of Brisbane, was quarantined and some plants were destroyed after TR4 was detected on March 3. Another quarantine some 180km north of the farm was revoked after final tests were negative, and no other cases have been disclosed. After an initial shutdown of the infected farm, the first truckloads of fruit left in April with harvesting allowed to resume under strict biosecurity arrangements. The government says it is not feasible to eradicate the fungus. Researchers like Wagenin- gen’s Kema say the disease will continue to spread, despite efforts to contain it, as long as susceptible varieties are being grown. “History is repeating itself,” banana author Koeppel said. “If you look at the map, this disease is marching.” With assistance from Nathan Gill in Quito and Stephen Stapczynski in New York A confined field trial of GM bananas at the National Agricultural Research Organisation in Kawanda, central Uganda. Pic: File 33 Field tests unde≥way in G≥eat Lakes a≥ea By KENNEDY SENELWA Special Correspondent BIOVERSITY INTERNATIONAL is co-ordinating field testing of high-yielding, disease-resistant bananas in the African Great Lakes region. The five-year project hopes to improve the livelihoods of smallholder farmers in Kenya, Uganda, Tanzania, Rwanda, Burundi and the Democratic Republic of Congo, which, produce a combined 22 million tonnes of bananas annually. The region is home to the East African highland bananas that are an important food and cash crop for more than 30 million people. But productivity is being challenged by low soil fertility, limited rainfall and pests and diseases such as black leaf streak, nematodes and weevils. The International Institute of Tropical Agriculture (IITA) said field testing of the new banana varieties seeks to develop superior East African highland cooking varieties. The Agricultural Research Institute of Tanzania is also participating in the project, which builds on over 20 years of breeding efforts by Uganda’s National Agricultural Research Organisation (NARO) and IIITA, leading to a set of 25 high-yielding hybrids related to East African highland bananas. “The new hybrids called NARI- TAs, after the two organisations, have been tested in Uganda with promising results, but need to be assessed further before they are released to farmers,” said IITA. Bioversity International will co- ordinate field testing of hybrids on three sites in Tanzania and two sites in Uganda. “We hope to develop hybrid banana varieties that will have at least 30 per cent higher yields and 50 per cent better resistance to at least three of the target pests and diseases compared with the current varieties grown by the farmers,” said Prof Tushemereirwe Wilberforce, director of research at NARO’s National Agricutural Laboratories.
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