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South Shore News

Workshop To Offer Update On Ailing Palm Trees

The Tampa Tribune
Published:   |   Updated: May 19, 2013 at 03:13 PM
TAMPA -

Hillsborough County's extension service will offer residents the latest information Thursday about a disease attacking cabbage palms in southern Hillsborough and northern Manatee counties.

The disease first showed up in the Tampa Bay area in Canary Island and other types of date palms about two years ago. It is similar to lethal yellowing that ravaged coconut palms in the 1960s.

Since, it has spread to cabbage palms - the Florida state tree.

Scientists first started noticing sickened cabbage palms - also known as sabal palms - last winter.

The first sign a tree has been infected is dropping its berries prematurely followed by the lower or oldest fronds turning brown or gray. Eventually, the disease moves to the leaf spear and kills the tree.

The disease is Texas Phoenix Palm Decline, called that because it first appeared in date palms in Texas in the late 1970s. The disease that has spread to cabbage palms is caused by the same type of bacteria that kills the date palms.

Scientists think the disease is spread by an insect but haven't found the culprit. A leafhopper, an insect that feeds on sap and can spread the bacteria that causes the disease, is a suspect.

Leafhoppers, about 1/8th of an inch long, move from tree to tree by hopping, flying or being propelled by the wind.

But there are a number of leafhopper species, any of which could carry the disease, said Mary Beth Henry, an agent with the University of Florida extension service in Hillsborough County.

The extension service plans to place sticky cards in palms where infected sabal palms have been found to capture insects to see if they can find one carrying the disease, she said.

Scientists don't know how far the disease has spread through the state's sabal palm population but the bacteria could cover the state.

"At this juncture, there's no way of controlling it," Henry said.

Unless an antibiotic is injected into an infected tree, the disease is fatal for the palm.

The only treatment is oxytetracycline HCI and should be applied by a certified arborist, Henry said.

The treatment should be done every three months. Costs vary but can reach $40 a tree. Once started, treatment cannot stop or the tree will die.

If you have an infected tree and don't intend to treat it, the palm should be cut down to prevent it from being a reservoir for the bacteria.

The treatment can also be preventive if the disease is found in sabal or date palms nearby. While prevention for the common cabbage palm may not be financially feasible, it may be worth the cost for more expensive palms such as the Canary Island date palm.

The extension service plans to place sticky cards in palms where infected sabal palms have been found to capture insects to see if they can find and identify any carrying the disease.

Even if the insect carrying the disease is identified, widespread use of insecticide to kill it is not likely, Henry said.

Diseased date palms have been found in Florida from southern Sarasota County to Pinellas County and east from Tampa to Lakeland.

The public workshop will be from 9 to 11 a.m. Thursday at the extension office at 5339 County Road 579, Seffner.

Register online at www.prohort.net or by calling (813) 744-5519, ext. 104.

Contact reporter Neil Johnson at (813) 259-7731.

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