Florida Keys

Key West’s official tree is being devoured by caterpillars

Caterpillars are feasting on Royal Poinciana trees in Key West.
Caterpillars are feasting on Royal Poinciana trees in Key West. Contributed

Key West’s majestic Royal Poinciana trees, with their fiery orange-red blooms and sprawling branches and roots, are under siege by a caterpillar that feeds on them at night.

The Royal Poinciana, which the city earlier this year crowned the official tree of Key West even though it is invasive, attracts a stubborn type of caterpillar that wildlife experts simply call the Royal Poinciana caterpillar.

At just under two inches long, the caterpillar is coated with black and brown stripes.

Rare for a member of the cutworm species, these caterpillars climb high trees and hide during the day in dirt, mulch or opened seed pods, according to Michelle Leonard-Mularz, of the Monroe County Extension Services, part of the University of Florida’s Institute of Food and Agricultural Sciences.

And they are gobbling up Poinciana canopies around town.

A Royal Poinciana tree blooms. Allison Diaz Miami Herald File

Arlo Haskell, who lives on Love Lane off Fleming Street in Old Town, said the Royal Poinciana in his yard went down quickly.

“They’re so abundant, they ate through the canopy — 20 percent of the tree — overnight,” Haskell said. “It’s insane. I was standing under this tree last week and it was thick, heavy shade and now it’s sunlight pouring through.”

The caterpillars are not regular visitors.

“This pest is unique in that there appears to be 10 to 15 years or so between major outbreaks,” Leonard-Mularz says.

The caterpillar problem dates back to 1942 in Key West and St. Petersburg. A year later, Stephen C. Singleton, the manager of the Key West Chamber of Commerce, reported the trees robbed of foliage by the caterpillars did not put out any new growth until June the following year, and some of the trees died.

More recently, an outbreak was discovered in Naples in 2006 when four 30- to 40-foot-tall Royal Poincianas lost half their foliage by October.

“All of the current infestations being reported in Monroe County are coming from Key West, with an isolated occurrence in Islamorada,” Leonard-Mularz said.

There’s no need to spray the canopy of the tree, Leonard-Mularz said in a brief study released Tuesday. That would not only be costly but harmful to other insects.

“A couple residents have reported successful results from treatment,” she wrote. “Bifenthrin products or Carbaryl (Sevin) would be effective. It’s very important to read the label! Whatever is used has to be labeled for the site you are using it on.”

Another method is to apply a burlap cloth trap around the tree’s trunk. The caterpillars will hide in the cloth and it could then be removed, washed in soapy water to remove the pests and then reapplied to the trunk, she said.

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