Deadly Palm Disease Reaches Highlands County

The first outbreak of a disease that is killing palm trees in other parts of the state was detected this week in Highlands County.

DNA testing confirmed that two large canary palms, part of the streetscape at Interlake Boulevard and Eucalyptus Avenue in Lake Placid, are infected with Texas Phoenix Palm Decline (TPPD).

To keep this new disease from spreading through the county, quick action is needed to either save an infected palm with a bactericide treatment or remove it, said John Alleyne, director of the Highlands County Cooperative Extension Service.

"Early detection is the key," he said.

Jim Fulton, public works director for Lake Placid, said the two infected canary palms will be removed on Monday. Each tree is valued at about $5,000, he said.

"Evidently, it (TPPD) can spread and we need to get them out, so we're going to take them down," Fulton said. "These trees are beyond saving."

If less than 25 percent of a palm's fronds show symptoms of TPPD, the tree can be saved by injection of the bactericide Oxytetracycline, Alleyne said. The application needs to be repeated every four months.

"If more than 25 percent (of the tree) is infected, it is advisable to get rid of the tree," Alleyne said. "At that point the Oxytetracycline would not be effective."

Alleyne said TPPD, first identified two and a half years ago in Texas, causes concern because it is not yet fully understood and kills about nine varieties of the Phoenix palm family.

"They are some of the most expensive palms in the landscape, and common in Highlands County," he said.

Palm trees susceptible to TPPD include the sabal or cabbage palm, the Florida state tree, as well as the Phoenix canaiensis (canary), sylvestris and dectylisera.

Alleyne described the two major symptoms of this disease.

First, the bottom fronds of a healthy palm normally turn yellow, then brown, die and fall off, while new green fronds spout at the top of the tree. When TPPD infects the tree, the bottom fronds never turn yellow. Instead, they turn from green to brown, die, and do not fall off.

Second, the bud, also called the spear leaves, from which new fronds sprout, dies and droops down.

"What you finish with," Alleyne said, "is a palm that looks like a 'mummified' tree. Its fronds are dead and look scorched and dry."

Confirmation of TPPD can be made only through DNA testing, which the extension service can provide, Alleyne said.

"I think the important thing right now is to get people alert and watching for this disease," he said. "If you have a concern, call the extension office (863-402-6540), and we'll come out and look at the tree."

If TPPD is suspected, Alleyne said, core samples will be taken and sent to the University of Florida's Research and Education Center in Fort Lauderdale for DNA testing.

"The first samples will be done free," he said. A landowner, though, would probably have to pay for subsequent DNA testing, he said.

Researchers have determined that TPPD is caused by a microplasm, a bacteria without cell walls.

"This is the same organism that was responsible a few years back for destroying the coconut palms," Alleyne said. "It wiped out a sizeable part of the coconut industry, up through the Yucatan Peninsula and into south Florida."

TPPD needs to be held in check until researchers can find out how it spreads, Alleyne said.

"Nobody knows what the vector (method of spreading) for this disease is," he said. "And until we know what the vector is we cannot have a correct method of controlling it.

"The University of Florida is working around the clock trying to identify the vector," Alleyne added. "Once you find the vector, you can administer control to get rid of the insect or whatever it is that is spreading it. The underpinning of a cure lies with finding the vector."

TPPD was first found in Florida in Manatee County about 18 months ago, Since then, the disease has spread to Hillsborough, Polk, DeSoto and Hardee counties and, on Wednesday, was confirmed in Highlands County.

"It breaks our heart to take these trees down, but that is what has to be done," said Mike Eisenhart, coordinator of Keep Lake Placid Beautiful. "These trees are the heart of the (beautification) project done years ago."

Once TPPD was diagnosed, he said, destruction of the trees became necessary under U.S. Department of Agriculture guidelines.

"We have to employ proper management practices, to protect nurseries and everyone in the area with similar trees," Eisenhart said.

Alleyne first alerted Highlands County residents and landscapers to watch out for this palm disease last August.

Ironically, on Tuesday, he provided information on TPPD at a symposium titled "Dead Palms Tell No Tales" at the Bert J. Harris Jr. Agricultural Center. About 35 people attended.

"We said that TPPD is not yet here in Highlands County, but we have to be watchful for it," Alleyne said. The next day he received confirmation of the disease in the two canary palms in Lake Placid.