Citrus greening newest danger to Florida

MIAMI – A tiny, disease-ridden insect lands on a bright green leaf of a healthy grapefruit tree, sucks out some nutrients and flutters away to the next plant.

In that instant, the once-productive tree begins its slow death. Its veins and stems are gradually choked by bacteria that cause citrus greening, a worldwide threat to citrus plants that today, along with citrus canker, menaces Florida’s US$9 billion (N$60,3 billion) industry.The first US discovery of the devastating disease was reported last month.Since then, the US Department of Agriculture, state scientists, university researchers and citrus growers have begun grappling with the newest foe to Florida’s famous and economically vital oranges, grapefruits and tangerines.”It’s devastating.It’s just hard to comprehend,” said Scott Hurley, vice president of Becker Indian River Fruit Company.”We’ve been battling the canker issue for a number of years and to have this thrown on top of it, it makes canker looks like child’s play.”Unlike canker, which creates unsightly lesions on fruit, the citrus greening disease is deadly to crops.It already has infected and killed trees in Southeast Asia and Africa and had started attacking crops in Brazil, the world’s largest producer of oranges, before being detected in Florida in September.The average productive life span of trees in areas affected by citrus greening has dropped from 50 or more years to 15 or less.There is no known cure for the disease, which does not harm people.”The major thing is that it affects the productivity of the tree and the quality of the fruit,” said Ronald Brlansky, professor of plant pathology at the Citrus Research and Education Centre in Lake Alfred.Experts are still debating what’s the most effective way to combat citrus greening.Some say the disease cannot be eradicated and that efforts should be directed at keeping it from spreading to uninfected regions.Others insist it’s too soon to determine the best solution.The state has relied on eradication to deal with citrus canker.An aggressive strategy requires the destruction of citrus trees within a 580-metre radius of one infected with canker.More than nine million trees already have been cut down.The disease itself does not kill the tree.Canker surfaced in Florida more than 10 years ago and is moved by wind-blown rain.Greening, however, is spread by a tiny insect called a psyllid.Officials said the disease probably arrived in Florida from infected Asian plant material.The disease affects the vascular system of the trees, eventually killing them.The fruit becomes lopsided and tastes bitter, rendering it unusable.Officials are concerned that the disease has spread throughout the state and perhaps travelled outside Florida on infected psyllids that hitch a ride on ornamental host plants that are commonly shipped to retailers.A quarantine is currently in effect for certain ornamentals in Miami-Dade.A sick tree will not show symptoms for a couple of years – and even when signs of the disease are present, samples still must be removed for lab testing because the telltale mottling and yellow discoloration can be evidence of other problems, such as nutrient deficiencies.No eradication or control strategy has been devised yet because of several unanswered questions, such as: How far has the disease spread? Would widespread fumigation work? How many trees have the disease? “We don’t know what to do,” said Hurley of Becker Indian River Fruit Company, which has 5 300 hectares of citrus.”Nobody has come up with any kind of guidelines.It’s just a guessing game right now.”-Nampa-APIts veins and stems are gradually choked by bacteria that cause citrus greening, a worldwide threat to citrus plants that today, along with citrus canker, menaces Florida’s US$9 billion (N$60,3 billion) industry.The first US discovery of the devastating disease was reported last month.Since then, the US Department of Agriculture, state scientists, university researchers and citrus growers have begun grappling with the newest foe to Florida’s famous and economically vital oranges, grapefruits and tangerines.”It’s devastating.It’s just hard to comprehend,” said Scott Hurley, vice president of Becker Indian River Fruit Company.”We’ve been battling the canker issue for a number of years and to have this thrown on top of it, it makes canker looks like child’s play.”Unlike canker, which creates unsightly lesions on fruit, the citrus greening disease is deadly to crops.It already has infected and killed trees in Southeast Asia and Africa and had started attacking crops in Brazil, the world’s largest producer of oranges, before being detected in Florida in September.The average productive life span of trees in areas affected by citrus greening has dropped from 50 or more years to 15 or less.There is no known cure for the disease, which does not harm people.”The major thing is that it affects the productivity of the tree and the quality of the fruit,” said Ronald Brlansky, professor of plant pathology at the Citrus Research and Education Centre in Lake Alfred.Experts are still debating what’s the most effective way to combat citrus greening.Some say the disease cannot be eradicated and that efforts should be directed at keeping it from spreading to uninfected regions.Others insist it’s too soon to determine the best solution.The state has relied on eradication to deal with citrus canker.An aggressive strategy requires the destruction of citrus trees within a 580-metre radius of one infected with canker.More than nine million trees already have been cut down.The disease itself does not kill the tree.Canker surfaced in Florida more than 10 years ago and is moved by wind-blown rain.Greening, however, is spread by a tiny insect called a psyllid.Officials said the disease probably arrived in Florida from infected Asian plant material.The disease affects the vascular system of the trees, eventually killing them.The fruit becomes lopsided and tastes bitter, rendering it unusable.Officials are concerned that the disease has spread throughout the state and perhaps travelled outside Florida on infected psyllids that hitch a ride on ornamental host plants that are commonly shipped to retailers.A quarantine is currently in effect for certain ornamentals in Miami-Dade.A sick tree will not show symptoms for a couple of years – and even when signs of the disease are present, samples still must be removed for lab testing because the telltale mottling and yellow discoloration can be evidence of other problems, such as nutrient deficiencies.No eradication or control strategy has been devised yet because of several unanswered questions, such as: How far has the disease spread? Would widespread fumigation work? How many trees have the disease? “We don’t know what to do,” said Hurley of Becker Indian River Fruit Company, which has 5 300 hectares of citrus.”Nobody has come up with any kind of guidelines.It’s just a guessing game right now.”-Nampa-AP

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