Gumbo Limbo Spiraling Whitefly
Gumbo Limbo Spiraling Whitefly

A wasp the size of a pin head may control the nuisance Rugose spiraling whitefly, which leaves a sticky white mess that becomes covered in black mold on everything from plants to cars and pools, University of Florida scientists say.

“Although the Rugose spiraling whitefly damages plants, what really gets people worked up is that it’s a huge nuisance because it makes a mess,” said Catharine Mannion, an entomology professor at the UF/IFAS Tropical Research and Education Center in Homestead, Florida. “You get a sooty mold on everything. It’s hard to get pools cleaned. People start chopping their trees down.”

But a new breakthrough shows the tiny wasp encarsia noyesi reduces the population of the Rugose spiraling whitefly, according to a new UF/IFAS-led study funded by the Farm Bill, through the U.S. Department of Agriculture.

After scientists from UF/IFAS and the Florida Department of Agriculture and Consumer Services identified the wasp and its potential, former UF/IFAS Post-Doctoral Associate Anthony Boughton confirmed biological information about the wasp.

Boughton did his research under the guidance of Mannion and fellow UF/IFAS entomology professor Lance Osborne. The study is published online in the journal Biological Control.

Boughton’s experiment, conducted in the laboratory and greenhouses at the Tropical REC from 2012-2014, confirmed that encarsia noyesi attacks and kills most stages of the whitefly, thereby reducing its population.

In addition to controlling a nuisance, the new finding likely saves Floridians untold amounts of money on pesticides and tree-cutting to control the whitefly, said Osborne, a faculty member at the UF/IFAS Mid-Florida Research and Education Center in Apopka, Florida.

Once Rugose spiraling whiteflies get on palm and gumbo limbo trees, cars, golf courses and homes people  use pesticides to kill them, Osborne said.

While UF/IFAS scientists were performing their experiments in Homestead, they conducted several investigations, he said. They tried to solve the problem in the field while performing the experiments in the lab in Homestead. The parasite worked so well in many locations around Florida that scientists have had trouble finding locations to conduct additional programs.

But as Mannion said: “These problems are never completely over. It’s never gone, but it’s greatly, greatly reduced.”

Rugose spiraling whitefly is most common in South Florida, but has been seen in 17 Florida counties, as far north as Orange, Osborne said.

Now that UF/IFAS scientists have found a biological control, homeowners who still experience what they deem an intolerable level of Rugose spiraling whiteflies, UF/IFAS researchers urge residents to use soap and water to get rid of the whitefly. If they use harsh pesticides, they’ll kill the natural enemies, in this case, encarsia noyesi.