Bed Bugs Are Even Peskier Than We Thought

A new study reveals that common over-the-counter bed bug eradication products are essentially ineffective

A new study shows that over-the-counter products sold to eradicate the bed bug, shown feeding above, are relatively ineffective Feedloader (Clickability)

First comes a mysterious difficulty sleeping through the night, then a splotchy, itchy rash and finally the alarming (and somewhat embarrassing) realization—your bed is infested with Cimex lectularius, the dreaded bed bug.

A new study published yesterday in the Journal of Economic Entomology has more bad news for those suffering from an infestation: Over-the-counter products like “foggers” and “bug bombs” do virtually nothing to kill the irritating pests.

Bed bugs have afflicted humans for a long time—they were even mentioned in the writings of Aristotle and Pliny the Elder—and a number of natural remedies have been used around the world, from black pepper to wild mint to eucalyptus oil. In the years after World War II, bed bugs were nearly wiped out in Western countries by heavy use of pesticides. Since the late 1990s, though, they have come back with a vengeance.

Scientists are unsure why they’ve made a comeback in recent years, but increased international travel and the bugs’ resistance to pesticides are suspected culprits. Bed bugs are especially likely to spread in densely populated cities and apartment buildings—and once they’ve infested your bed, as bed bug sufferers know well, they’re extremely difficult to eradicate. The tiny bugs, just 4 to 5 millimeters in length, can live for up to a year without feeding, and their eggs can lodge invisibly in the seams of sheets or pillowcases.

Most infestations are detected when the creatures do begin to feed, piercing the skin to suck out blood and leaving a series of telltale blotchy red marks. Since bed bugs can become fully engorged with blood in just a few minutes while you’re asleep, catching one in the act is extremely rare. Infestations can also be detected by a characteristic smell, similar to that of over-ripe raspberries, and pest control companies often use dogs to recognize the odor.

The new study, by Susan Jones and Joshua Bryant of Ohio State University, evaluated consumer bed bug control products. They tested the effectiveness of three different products on a five bed bug populations collected from the field, and the results were consistently dismal: The bugs showed essentially no adverse effects after two-hour exposures to the spray insecticides. One population did show an increase in mortality, but only when the bugs were directly hit by the spray, something the authors say is exceedingly rare in real-life applications since the bugs burrow deep into mattresses and fabrics.

“These foggers don’t penetrate in cracks and crevices where most bed bugs are hiding, so most of them will survive,” Jones said in a press release. “If you use these products, you will not get the infestation under control, you will waste your money, and you will delay effective treatment of your infestation.”

One reason the the products are so ineffective, the authors speculate, is an especially concerning one: pesticide resistance. Excessive use of products such as these, which contain the pesticide pyrethoid, might be causing more and more bed bugs to become entirely resistant to the same chemicals that used to wipe them out easily.

So what are you to do if hit with a bed bug infestation? Bringing in a pest professional to kill the creatures is likely more effective than using the store-bought products, but increasing resistance can also render this approach ineffective. Oftentimes exterminators will recommend that you throw out mattresses and other pieces of furniture that bed bugs have infested. Using extreme cold or heat to kill the bugs is an increasingly popular solution, but these techniques also sometimes leave behind founder populations that generate an infestation afterward.

The bottom line—once an infestation of bed bugs has taken hold, it’s extremely difficult to get rid of. Experts advise that early detection and immediate treatment by professionals is the best chance you have of eradicating it entirely. But buying a pesticide over-the-counter and hoping for the best really doesn’t work.

Get the latest Science stories in your inbox.