Disease could kill hundreds of Pinellas trees

A single case of laurel wilt disease was discovered about a year and a half ago in a Pinellas County park. Now, its spread to hundreds of trees and there is nothing that can be done to save any of them.

Once the tiny Redbay ambrosia beetle bores into a tree, the fungus spread by its mouth will have already done too much damage.

All sorts of trees are at risk -- swamp bay and red bay laurels, and especially avocado trees.

"If you were to look on a penny, it's about the size of three of the numbers, like 2007, it'd be like the last three numbers, that's about the length of it, so it's very, very tiny," said Jane Morse with the Pinellas County Extension Office.

Only 16 months ago, a single tree was found infected at John Chesnut Park. Hundreds of trees there are looking sad and brown.

The beetle and the disease are expected to migrate to trees in nearby Brooker Creek Preserve.

"That the beetle is killing the tree," said Gloria Gere with John Chesnut Park, as she walked us around to show us the damage.

"It's a bay tree," she pointed to swamp and red bay trees. Also, sassafrass, pondspice and one of Florida's most highly-prized fruit trees, avocados, top the endangered list.

The beetle was first found in Georgia and South Carolina ports in 2002. Laurel wilt spread down to Duval County by 2005 and now it's in Pinellas County. Some of the obvious symptoms include brown, withered leaves.

Also, one of the deadliest giveaways that the beetle and the fungus have gotten into a tree is a telltale ring of sawdust around the base. Chances are if it's gotten that far, the tree is a goner.

"It's pretty rapid, probably within about 15 months or so, you can go from hardly any mortality, up to about 92 percent mortality," Morse said.

The fungus is drawn into the tree's vascular system and shuts it down, causing the leaves to wilt and the tree to essentially starve and die. Disposal is tricky, and authorities say not to transport it.

"It's best if you can bury it, or burn it, or you could chip it and shred it and use it as mulch on-site," Morse said.

There is an anti-fungal that can be injected into the Redbays if the disease is caught early enough. Avocado trees cannot be treated, though, because the chemicals can be transferred into to the fruits.

"Just keep an eye out. If you start seeing major wilt on either, if you have an avocado tree or if you have a Redbay tree, that's pretty good indication that it's probably infested with the laurel wilt, and you want to take that tree out as soon as possible," Morse said.

The hope is to get a handle on it and control the spread of laurel wilt here in Central Florida, before it trickles down toward Dade County, where avocado production accounts for about $13 million a year.