BATON ROUGE, La. (AP) — The Louisiana Department of Agriculture and Forestry and the LSU AgCenter are beginning a two-year study to find out which varieties of satsuma trees are most resistant to the dangerous disease called citrus canker.

The bacteria damage all kinds of citrus from kumquats to grapefruit, causing a gradual decline until the tree stops producing any fruit.

LSU's analysis of samples collected for the department's citrus pest survey found that some satsuma is resistant, but not which, according to a news release Tuesday from the agriculture department.

The study will look at five cultivated varieties — or, as scientists call them, "cultivars" — of satsuma, said Raghuwinder "Raj" Singh, a plant pathologist at the AgCenter.

They'll keep an eye on healthy trees in areas with known infections, to see when infections show up, how many trees become infected and how quickly or slowly the infections develop.

"Citrus trees, especially satsumas, are grown commercially and are the backyard fruit tree of choice in south Louisiana," department Commissioner Mike Strain said. "We hope this project will ensure that this tradition will carry on for many generations to come."

The disease was first identified in Louisiana in 2013, in New Orleans' City Park. Until then, it had been found only in Florida since 1945. It has since spread into parishes where citrus is grown commercially.

City Park is among five sites where trees will be checked, Singh said in an email.

He said others include yards and an abandoned grove. None is in a commercial grove, he said.

Singh said the agriculture department is helping to find infested sites and to ensure all quarantine restrictions are followed.

A U.S. Department of Agriculture specialty crop block grant is paying for the study, the agriculture department said.

Citrus canker is one of two diseases that have quarantined all of Florida's citrus: 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.