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Citrus industry stung again
United States
Sunday 09 September 2007
Dozens of dead orange trees lie stacked here among vast green rows of grove.
Farmers felled them still bearing fruit, but these trees were really killed some time ago. All it took was a tiny insect's bite to deliver a fatal crop disease called citrus greening, a bacteria harmless to humans but deadly for the thousands of trees infected since its recent arrival in Florida.
Greening has bedeviled other areas of the world for decades and is believed to have arrived in Florida on infected Asian plant material. The disease kills a plant's vascular system and sours fruit, making it unusable.
There are no natural enemies here to the foreign insect that spreads greening - the Asian citrus psyllid - and predators can't be introduced. Pesticides that kill the psyllid also kill beneficial insects that control other bugs.
Genetic solutions are in the works for both plants and sprays, but for now farmers can do little but watch groves closely and clip infected trees.
That requires a lot of work and money. The early signs of greening are subtle - yellowing, or mottled leaves - and easily confused for other problems.
Southern Gardens Citrus, a Hendry County company owned by U.S. Sugar and among the state's top producers, is paying US$300 to US$400 more an acre on greening detection, a one-third increase in production costs.
In October 2005, the Clewiston-based company became one of the first commercial producers to test positive for greening.
''We were hoping it was limited to a couple acres. We realized there were thousands of acres,'' said Tim Gast, citrus horticulturist for Southern Gardens.
Gast said so far the company has cut down nearly 100.000 trees - enough to affect production.
Southern Gardens relied on organic oils and copper sprays to control bugs, but greening has forced them to use more harmful pesticides, Gast said.
Farmers felled them still bearing fruit, but these trees were really killed some time ago. All it took was a tiny insect's bite to deliver a fatal crop disease called citrus greening, a bacteria harmless to humans but deadly for the thousands of trees infected since its recent arrival in Florida.
Greening has bedeviled other areas of the world for decades and is believed to have arrived in Florida on infected Asian plant material. The disease kills a plant's vascular system and sours fruit, making it unusable.
There are no natural enemies here to the foreign insect that spreads greening - the Asian citrus psyllid - and predators can't be introduced. Pesticides that kill the psyllid also kill beneficial insects that control other bugs.
Genetic solutions are in the works for both plants and sprays, but for now farmers can do little but watch groves closely and clip infected trees.
That requires a lot of work and money. The early signs of greening are subtle - yellowing, or mottled leaves - and easily confused for other problems.
Southern Gardens Citrus, a Hendry County company owned by U.S. Sugar and among the state's top producers, is paying US$300 to US$400 more an acre on greening detection, a one-third increase in production costs.
In October 2005, the Clewiston-based company became one of the first commercial producers to test positive for greening.
''We were hoping it was limited to a couple acres. We realized there were thousands of acres,'' said Tim Gast, citrus horticulturist for Southern Gardens.
Gast said so far the company has cut down nearly 100.000 trees - enough to affect production.
Southern Gardens relied on organic oils and copper sprays to control bugs, but greening has forced them to use more harmful pesticides, Gast said.
