UF researchers turn up the heat on bedbugs with new low-tech treatment method

July 7, 2009

GAINESVILLE, Fla. — Bedbug infestations are notoriously hard to eliminate, but University of Florida researchers have developed a low-cost, low-tech method to kill the bloodsucking insects in furniture and bedding, using heat.

With less than $400 in equipment they created a portable chamber big enough for a bed or dresser. Heaters inside the chamber gently raise its air temperature to a minimum of 113 degrees Fahrenheit — enough to destroy the insects but not damage the items.

Treatment takes from two to seven hours, said urban entomologist Phil Koehler, a professor with UF’s Institute of Food and Agricultural Sciences. In a study, the method killed 100 percent of bedbugs in nine out of 11 trials conducted in dormitories and apartments.

The study appears in the current issue of Journal of Economic Entomology.

“You’re very limited in what you can do to fight bedbugs,” said Koehler, an author of the study. “This is a good way to relieve infestations in bedding and other items people have close contact with, and it controls all life stages of bedbugs.”

Koehler said a private company has patented a system for heat treatment of entire buildings. The UF researchers developed their method as an experiment, to see if portable heating chambers could be used together with pesticides to treat rooms quickly.

This approach can be used to treat individual units in large apartment buildings and dormitories without displacing other residents, he said.

The key, Koehler said, is raising all air in the chamber to a minimum of 113 degrees. The researchers used digital thermometers with probes placed in some of the treated items so they could continuously monitor temperatures inside the chamber.

To ensure effective treatment, the probes must be put in places the heat is least likely to reach. “It’s somewhat like cooking a turkey,” Koehler said.

Clothes, sheets and other bedding can also be placed in a clothes dryer at high heat for about 15 minutes to kill all bedbugs, he said.

For the study, researchers placed vials of live bedbugs inside furniture items, and then assembled the chamber around the furniture, said Roberto Pereira, a research associate scientist who works with Koehler.

The method killed 100 percent of the bedbugs in rooms with carpeted floors, but only killed about 83 percent when used on tile because the heat wasn’t contained effectively, Pereira said.

The project’s origins go back to 2006, when Wayne Walker, pest manager for UF’s campus housing, was seeking new ways to treat occasional bedbug infestations.

Discussions with Koehler led to several attempts to develop a heat treatment for furniture. Eventually Koehler settled on a combination of oil-filled electric space heaters, electric fans to circulate air and polystyrene insulation board to form the chamber walls.

The researchers don’t plan to develop a commercial product but will continue researching the effects of heat treatments on bedbugs, Pereira said.

Portable heat chambers may be best suited for situations where bedbugs are known to infest a small area, such as a single piece of furniture or a suitcase, said Michael Botha, president of Sandwich Isle Pest Solutions, in Pearl City, Hawaii.

Botha, who has a longtime interest in alternative pest-control methods, said his company is experimenting with chambers for treating luggage. Travelers sometimes unwittingly pick up bedbugs in hotels and bring them home in suitcases.

But for large-scale infestations, he says, the solution may lie in the commercial heat treatment used for entire buildings.

Homeowners should not attempt to build their own heat treatment chambers, the UF researchers said, warning that it could lead to fires.