Why Bed Bugs Are Becoming So Much Harder to Kill
by: Amanda MacMillan
Bed bugs are developing resistance to two common insecticides, according to a new study in the Journal of Economic Entomology. Experts warn that many infestations can no longer be defeated with chemicals alone.
The common bed bug, Cimex lectularius, has previously shown considerable resistance to several other insecticides, including a commonly used one called deltamethrin. The reduced effectiveness of these chemicals is considered a main cause of the bed bug’s resurgence over the last decade, especially in big cities.
To find out if bed bugs were also developing resistances to two other common insecticides, bifenthrin and chlorfenapyr, Purdue University researchers gathered 10 different bed bug populations from Indiana, New Jersey, Ohio, Tennessee, Virginia and Washington, DC, and exposed them to the chemicals for seven days.
In five of these populations, they found reduced susceptibility to bifenthrin—meaning that more than 25% of the bed bugs survived. Three populations also had reduced susceptibility to chlorfenapyr.
Concerns about insecticide resistance aren’t new, says lead author Ameya Gondhalekar, research assistant professor at Purdue’s Center for Urban and Industrial Pest Management. “The longer you use any product for the control of a particular pest, the more resistance issues you are going to have,” he says. In 2015, a University of Kentucky survey found that 68% of pest management professionals considered bed bugs the most difficult pest to control.