A U.S. Department of Agriculture Animal and Plant Health Inspection Service laboratory confirmed the identification, according to a news release.
This marks the first time that the bacterial citrus disease has been found in Louisiana.
The disease has been present in Florida since 1995.
The discovery in Louisiana marks the second state in which citrus canker has been found.
The Louisiana Department of Agriculture and Forestry is conducting a survey to determine whether the disease has spread beyond the three trees from which samples were collected.
Citrus canker causes lesions on fruit and leaves but is harmless to humans or other animals. It can be spread by wind-driven rain, movement of infected plant material, or contaminated tools or equipment.
To report any suspect trees, contact Bill Spitzer, state plant health director, at email@example.com or (225) 298-5410.