NEW ORLEANS (AP) — Two incurable citrus diseases continue to spread in Louisiana, but neither citrus greening nor citrus canker has been found in commercial orchards, says the director of the LSU AgCenter's Plant Diagnostic Center, Raj Singh.
Citrus greening turns fruit bitter and ultimately kills the tree. Canker-infested fruits are edible but have brown spots that make them hard to sell. The disease, which also causes spots on leaves and twigs, also makes trees drop fruit and leaves prematurely.
The Louisiana Department of Agriculture and Forestry has $175,000 in federal money to check for the diseases. "There is a focus on Plaquemines Parish where the citrus industry is centered," department spokeswoman Veronica Mosgrove said.
Singh said he's more worried about canker because it spreads far more swiftly.
Canker bacteria thrive in heat and are spread by wind and rain, making the disease almost impossible to control, he said. Greening is spread by tiny bugs called citrus psyllids, which can be controlled by insecticide.
Citrus canker is one of two diseases that have quarantined all of the citrus in Florida, where it's a $9 billion business. Plants, leaves and twigs cannot leave the state unless they're certified free of the diseases. Fruit — including fruit grown in home yards — must be treated at a commercial packing house and federally certified before crossing the state line.
But greening is having a much bigger effect on Florida's crop this year. U.S. Agriculture Secretary Tom Vilsack said last month that the agency is putting $31.5 million into research on greening.
Singh said Louisiana's survey could indicate whether state quarantines are needed for canker, which also causes brown spots on leaves and twigs.
The disease was found last month in St. Bernard Parish, Singh said. It showed up last year in Louisiana for the first time since 1940. Canker was confirmed in four New Orleans-area parishes including Plaquemines.
"We keep an eye out, but we have 5,000 orchard trees" — too many to check each one regularly, said grower Ben Becnel Jr. of Belle Chasse.
Plaquemines Parish grew $3.7 million of Louisiana's $5.4 million citrus crop last year. Growers in Iberia, Lafourche, St. Mary and St. James parishes sold $655,000 to $115,000 worth of fruit; another 13 parishes reported crops worth about $5,000 to $93,000, according to the AgCenter.
Singh said greening was found in the Gentilly area of New Orleans in March. It had previously been found in 2008 in New Orleans neighborhoods on the Mississippi River's west bank and in Washington Parish north of Lake Pontchartrain.
"We have some friends in Florida that have both of those, canker and greening. From what he's telling us, canker is nothing compared to greening" because canker-infested fruit can be eaten, Becnel said.
Singh said people shouldn't touch canker-infested fruit lest they spread the bacteria to other trees they touch.
Mosgrove said owners of infected trees in quarantined areas are encouraged to cut the trees and send them to a designated landfill in the quarantine area. St. Charles, Jefferson, Orleans, St. Bernard, and Plaquemines parishes are quarantined for canker; Orleans, and Washington parishes for greening.
People who remove canker-infested trees should double-bag the debris, using heavy-duty bags, Singh said.