LSU AgCenter agents learn about citrus pest

News Release Distributed 07/22/08

Now that the Asian citrus psyllid has been discovered in Louisiana, LSU AgCenter agents are learning what to look for to help stop it.

Agents from the citrus-growing regions of the state attended a training session July 10 to learn how to identify the pest and how to deal with calls from concerned citrus growers.

In addition to classroom training, the agents learned to identify the pest on citrus trees in Jefferson Parish.

Dr. Natalie Hummel, LSU AgCenter entomologist, said the pest is known to transmit greening disease, which can cause significant damage to Louisiana’s citrus industry.

“We are trying to be proactive in the control of this disease since we seem to have caught it in its early stage of infection,” she said.

In June, the first infected tree in the state was discovered and diagnosed in a backyard in Orleans Parish in June.

Hummel said a challenge to finding psyllids in an urban area is that the pests are known to transmit greening disease from tree to tree as they feed.

“Disease may spread quicker in an urban environment because there are few pesticides to control psyllids in backyard citrus,” she explained.

Since that first infestation was discovered, the Louisiana Department of Agriculture and Forestry and the U.S. Department of Agriculture, the regulatory agencies for this type pests, have begun surveying citrus trees from New Orleans to Calcasieu Parish to determine the extent of the problem.

A quarantine has been placed on citrus trees moving out of the affected areas of the state.

Dr. Bobby Fletcher, the LSU AgCenter’s area horticulture agent in Terrebonne Parish, said the pest has been found in a wide area of South Louisiana.

“The insect has been identified in Jefferson, Lafourche, Orleans, Plaquemines, St. Charles, and Terrebonne parishes,” Fletcher said.

It’s possible that a tree could be infected with greening disease and not show any signs for six months to two years, said Dr. Don Ferrin, LSU AgCenter plant pathologist.

“For this reason, we feel that getting our people aware of what to look for just puts us that much further ahead in trying to slow down this pest and the disease,” he said.

Hummel said the insect was first identified in Florida citrus in 1998, and greening disease first appeared there in 2000. At that time Florida officials realized the insect and greening disease were widespread across the state.

Texas is the only other state with the insect at this time, but greening disease has not been found there, she said.

Hummel, who has been working closely with this pest, said the plan is “to get out there in our commercial areas with an aggressive plan so we can keep the pest populations low to hopefully prevent widespread occurrence of the greening disease.

The LDAF destroyed the one tree that was found to be infected with the greening disease so far. “The homeowner understood the importance of the disease and willingly allowed LDAF to destroy the tree,” Hummel said.

The disease has no treatment, so the only thing growers can do if they find the disease is to remove the diseased trees, said Dr. Dale Pollet, LSU AgCenter entomologist.

Pollet said once greening disease is in a tree, psyllids can spread it to other trees.

“The nymph can get infected and will continue to carry the disease through adulthood,” he said. “You can have up to 30 generations of this pest per year.”

More information on the Asian citrus psyllid is available from LSU AgCenter parish agents on the LSU AgCenter Web site at


Don Ferrin at (225) 578-8537 or
Bobby Fletcher at (985) 446-1316 or 
Natalie Hummel at (225) 578-7386 or
Dale Pollet at (225) 578- 578-2370 or

Writer: Johnny Morgan at (225) 578-8484 or

7/22/2008 1:05:29 AM
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