AUSTIN, TEXAS — As bedbugs become more resistant to various pesticides, other do-it-yourself defenses are growing in importance. But new tests give several popular methods of homespun bedbug defense low grades.
Rubbing alcohol is often recommended for killing bedbugs, for example. But spraying a group of the insects with it left about half alive four days later, Changlu Wang reported November 13 at the Entomology 2013 conference. His research team at Rutgers University in New Brunswick, N.J., also found that mothballs failed to wipe out bedbugs after 7 days in a plastic bag full of infested clothes. Eggs and immature bedbugs survived the mothball treatment well, and only between 44 to 60 percent of adult males died.
In spite of these and other underwhelming test results, Wang encourages no-pesticide, DIY tactics. The common bedbug (Cimex lectularius), for decades so rare in the United States that many entomologists had never seen a wild one, has resurged in homes, hotels, planes, ambulances and offices.The watchful eyes and mindful habits of residents give a place its best chance of preventing infestations or stopping them early. And since bug populations are growing increasingly resistant, pesticides, especially those available to regular folks without a professional license, may or may not help.
The difficulty of controlling today’s bugs came up at the meeting on November 12, when Dini Miller of Virginia Tech in Blacksburg summarized bedbugs’ growing resistance to pesticides. Among the bugs’ defenses are variations in enzymes that can now detoxify certain pesticides and an enhanced outer cuticle that reduces pesticides’ penetration Miller finds bug populations that combine such defensives for a formidable mix.
Bringing back DDT, a fantasy Miller said she often hears from people fighting infestations, won’t help, because bedbugs demonstrated decades ago they evolve resistance to it. “We got about eight good years out of it,” she said.
A commercial blend of essential oils turned out to have a major drawback under likely real-world conditions. In a lab where bugs had no chance to bite anybody, treatment with Bed Bug Fix™ had killed 92 percent of bugs by the end of two weeks. (Untreated bugs can survive much longer without food.) But when researchers sprayed bugs and allowed them to feed, as they might in a home, the insects survived. Just why the results varied isn’t clear, Wang says.
Preventing outbreaks of such resilient bugs is obviously the best course. Ultrasonic bedbug repelling devices are popular, but they won’t do it, Wang said. In a survey of 23 places infested with bedbugs, five had an ultrasonic repeller.
Wang does support some tools and strategems for a home campaign against bedbugs. He recommended bug-blocking mattress casings, washing clothes in hot water and drying them at high temperatures, and, if people have access to the equipment, steaming mattresses and other surfaces. He’s also had good results testing dry ice in a big plastic bag as a low-cost fumigation chamber for toys and other hard-to-launder items. He’s concerned, however, that people might hurt themselves if they handle dry ice improperly.
His talk inspired discussions among bedbug entomologists about vacuuming to reduce populations of bedbugs. “There are things you can’t steam,” said Mark Goodman of the University of Kentucky in Lexington. However, vacuuming done wrong can make things worse if the vacuum cleaner itself gets infested, says Richard Cooper, a Rutgers graduate student with a family pest control company.
With all the challenges of bedbug control, Goodman says he sees people so overwhelmed that they do nothing but try to endure. Resistant as bedbugs are to many pesticides and superb as they are at hiding, he encourages people to try simple things that can at least knock down pest numbers. “Bedbugs aren’t resistant to my foot,” he says.
Editor’s Note: This story was updated on November 25, 2013, to correct the number of days for the mothball test, the number of places with outbreaks surveyed and the number of those places that had an ultrasonic repeller.