Mar. 2, 1999 ST. PAUL, MN (March 1, 1999) -- Black Sigatoka, a fungal disease with a voracious appetite for banana foliage, is spreading through banana production regions of the world. Most recently, the disease was reported in Florida. Since bananas are a staple food and a major export product in much of the developing world (they are the world's fourth most valuable food crop), black Sigatoka is imposing a heavy toll on the food security and export economies of the producing nations. Fortunately, plant pathologists are taking the lead with other scientists to breed bananas that are resistant to the disease.
"The black Sigatoka pathogen thrives under the warm, wet conditions that are found in the tropics," says Randy Ploetz, plant pathologist with the University of Florida and member of the American Phytopathological Society. "In such environments, black Sigatoka severely damages banana leaves and reduces a plant's ability to capture the sun's energy. As a consequence, fruit production can be reduced by 50% or more. Black Sigatoka also causes premature ripening, which is a serious defect in exported fruit."
Infected planting material and leaves, which are often used in the developing world as packing materials, are usually responsible for long-distance spread.
"In order to reduce the impact of this disease, it is essential that resistant bananas be developed," says Ploetz. "Chemical control is available but expensive and generally not available for poor farmers who depend on this crop. Moreover, the pathogen has a tendency to develop resistance or tolerance towards some types of fungicides."
Historically, genetic resistance in banana to black Sigatoka and other diseases has been poor. The situation is changing, however, as a result of new hybrids that are being developed by banana breeding programs in Guadeloupe, Honduras, Nigeria, Uganda and other countries. "Products of the breeding programs are bound to play increasingly important roles in subsistence agriculture," says Ploetz. "Whether new hybrids eventually replace cultivars that are used by the export trades, however, remains to be seen. In the end analysis, we believe that resistant bananas will be our best defense against diseases in subsistence and export situations alike."
For more information on black Sigatoka, visit the APS March web feature story with photographs and links to additional sites at http://www.scisoc.org. The American Phytopathological Society (APS) is a professional scientific organization dedicated to the study and control of plant disease with 5,000 members worldwide.
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