Bedbugs: Have They Built Up A Resistance To Chemical Treatments?

Researches at Virginia Tech have discovered that bed bugs are becoming increasingly immune to a common class of insecticide chemicals, according to a recent study.

Researchers examined how the bugs did when they were exposed to two classes of chemicals--including neonicotinoids, or neonics, and pyrethroids. One population of the bugs were isolated from pesticide use for the past 30 years while the others were never exposed to the classes of chemicals. Furthermore, researchers found that another group collected in New Jersey that were since isolated developed a pyrethroid tolerance but had never been exposed to neonics. And from there, two more populations were collected recently from homes in Michigan and Cincinnati, Ohio.

"Unfortunately, the insecticides we were hoping would help solve some of our bed bug problems are no longer as effective as they used to be, so we need to reevaluate some of our strategies for fighting them," study co-author Troy Anderson, an assistant professor of entomology in the Virginia Tech, said in a news release. 

While small amounts of neonics and pyrethroids killed at least 50 percent of the long-isolated bugs, it took several thousand times more of the chemicals to achieve a similar result with the bed bugs from Ohio and Michigan.

Both of the modern populations from the Midwest were 33,333 times more resistant to a common insecticide called acetamiprid.

The New Jersey bed bugs were also more resistant to neonics, even though they had never before been exposed. Researchers think detoxifying enzymes developed via their pyrethroid tolerance helped them fend off the new chemicals.

"While we all want a powerful tool to fight bedbug infestations, what we are using as a chemical intervention is not working as effectively it was designed and, in turn, people are spending a lot of money on products that aren't working," said Anderson, via Phys.org.

The researchers suggest that feeding "stimulates detoxification enzymes responsible for insecticide resistance," which may explain why a bed bug's survial increases with bloodmeals. Therefore, using insecticides in tandem with other control methods would work as the best option. 

"Incorporating non-chemical methods into bed bug control is very important in order to achieve good results," said Singh. "Some examples of non-chemical methods include vacuuming visible bed bugs, applying steam to furniture and baseboards, laundering bed sheets and infested clothing, encasing mattresses and box springs with bed bug encasements, and installing interceptors under the legs of beds and upholstered furniture."

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