“Lesions are visible on both sides of the leaves with water-soaked margins surrounded by a yellow halo,” Singh said. “As the lesion ages, the center becomes raised and corky and may fall out, giving it a shot- hole appearance.”

Similar lesions are present on the twigs but without the water-soaked margins and yellow halo.

The bacterium enters the host tissue through natural openings and wounds. It is not spread by insects or other organisms, but the wounds caused by citrus leaf miner may serve as infection sites, Singh said.

Bacteria may survive in old lesions, and under favorable environmental conditions they may ooze from these lesions and disperse a short distance by wind and rain.

Long-distance movement of citrus canker is generally attributed to human movement of infected citrus material and storms such as hurricanes and tornadoes.

“We highly urge Louisiana residents to not move any infected citrus plant material within or out of state and to report any suspected trees to Bill Spitzer, state plant health director at william.e.sptizer@aphis.usda.gov or 225-298-5410,” Singh said.