- Associated Press - Tuesday, May 12, 2015

BATON ROUGE, La. (AP) - Scientists at the LSU AgCenter say a new plant disease that can kill an ornamental shrub called Chinese fringe flower or loropetalum has been found at a Louisiana nursery.

Plant pathologist Raj Singh won’t say if the nursery is in north or south Louisiana. The bacterium “Pseudomonas savastanoi” (soo-duh-MOH-nuhs suh-VAS-tuh-noy) was confirmed last month, he said Monday.

Loropetalums are members of the witch hazel family that, in the Spring, are covered with pink or white flowers with long, thin petals. They can be grown as ground cover, hedges and small trees.

Alabama scientists identified the bacteria in 2013 as causing small, rough galls or knots on loropetalum shoots and stems. That report said it damaged or killed 30 to 40 percent of the loropetalums at two south Alabama nurseries in 2012, and similar symptoms were seen earlier in central Alabama, North Carolina and Georgia.

The LSU AgCenter sent a news release Monday describing the disease and how to deal with it.

“If the disease is detected at an early stage when galls are present on small shoots, removing infected plant material several inches below the gall helps reduce disease spread,” Singh said.

But the galls are small and easy to miss. If they’re on the main stem, the entire plant should be removed, he said. Singh said nurseries should quarantine and regularly inspect loropetalums for three or four months, disposing of any that are infected, and buyers should inspect stems and shoots for galls or knots.

The plants originally were Chinese imports. The white-flowered variety was imported in the late 1800s, but it was the pink varieties, imported in the 1980s and ‘90s, that made the species popular, according to the Clemson Cooperative Extension Service website.

Singh said the bacteria is known to cause galls on olives and oleanders, and can also be found in ash, privet and forsythia.

It develops rapidly during extended periods of wet, warm weather, spreading from plant to plant in water from rain or sprinkler irrigation. It can also be spread by contaminated cutting tools or through infected cuttings.

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Online:

Alabama report: https://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-11-12-1011-PDN

Pseudomonas savastanoi: https://www.ncbi.nlm.nih.gov/pubmed/22805238

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