Foc-TR4 Fungus, Devastating To Cavendish Bananas, Confirmed In Jordan, Mozambique
A variant of a fungus that rots and kills the main variety of export banana has been found in plantations in Mozambique and Jordan, raising fears that it could spread to major producers and decimate supplies. The pathogen, which was until now limited to parts of Asia and a region of Australia, has a particularly devastating effect on the popular Cavendish cultivar, which accounts for almost all of the multibillion-dollar banana export trade. Expansion of the disease worldwide could be disastrous, say researchers.
The disease is caused by strains of a soil fungus called Fusarium oxysporum f. sp.cubense (Foc). A strain of Foc previously wiped out the Gros Michel cultivar, which was the main exported banana variety from the nineteenth century until the 1950s. In response, the industry replaced Gros Michel plants with the Cavendish variety, which is resistant to that Foc strain. But Cavendish is susceptible to the new Foc Tropical Race 4 (Foc-TR4) strain, and could meet the same fate as Gros Michel if the fungus reaches Latin America, the world’s leading banana exporter, says Rony Swennen of the Catholic University of Leuven in Belgium, and a banana breeder at the International Institute of Tropical Agriculture in Dar es Salaam. “It’s a gigantic problem,” he adds. Although Foc strains spread slowly, they are almost impossible to eliminate from soil.
Foc-TR4 was first detected in Asia in the 1990s, and is now found in Taiwan, Indonesia, Malaysia, the Philippines, China and northern Australia (see ‘Fruit threat’). The outbreak in Jordan, reported on 29 October (F. A. Garcia et al. Plant Dis. http://doi.org/qd3; 2013), was the first to be described outside those nations. The Mozambique outbreak was reported last month.
Nobody is sure how the fungus arrived in Jordan or Mozambique. Migrant workers from Asia might inadvertently have brought contaminated soil with them. Another possibility is the import of infected rhizomes — the stems from which banana plants propagate. But much of the Cavendish industry now uses tissue culture, which produces pathogen-free plantlets.
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http://www.nature.com/news/fungus-threatens-top-banana-1.14336
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