Citrus canker, a serious disease of citrus, was recently found on trees in East Baton Rouge and Livingston parishes, according to LSU AgCenter plant doctor Raj Singh.
Citrus canker is a highly contagious bacterial disease that was first detected around 1914 in Louisiana and declared eradicated by 1940. But the disease reappeared in the state in June 2013.
The disease is known to cause defoliation, premature fruit drop, blemished fruit and tree decline. Severely infected trees ultimately may stop producing fruit.
“The pathogen produces raised, corky lesions on upper and lower surfaces of the leaves,” Singh said. “Lesions on the upper surface are surrounded by a yellow halo, whereas older lesions on the lower surface tend to lose the yellow halo.”
The disease can spread rapidly in Louisiana’s hot and humid climate, he said.
There are no effective treatments to eliminate the disease after the infection has occurred. The disease affects citrus only, and all citrus varieties are susceptible.
After the reappearance of the disease in the state in 2013, a quarantine zone was established for Jefferson, Lafourche, Orleans, Plaquemines, St. Bernard, St. Charles, St. James and St. John parishes to restrict the movement of citrus trees and other materials that might spread the disease, Singh said.
Federal and state quarantine regulations prohibit movement of citrus plants, any plant parts, clippings or fruit out of the quarantined zone.
“In addition, federal restrictions require that tools, equipment and personnel performing any service work on properties where a citrus tree is present must be disinfected with a bacterium-killing solution before leaving the property,” Singh said.
The quarantine zone does not include East Baton Rouge and Livingston parishes. The affected plants have been removed from the two nurseries where the disease was found, according to the Louisiana Department of Agriculture and Forestry.
If you believe your citrus trees have citrus canker, contact the U.S. Department of Agriculture at 225-298-5410 or the LDAF Horticulture and Quarantine Division at 225-952-8100.
More information about citrus canker can be obtained by calling Singh at 225-578-4562 or emailing firstname.lastname@example.org.
A copy of the LSU AgCenter Citrus Canker factsheet, Publication No. 3269, is available online here.