I direct you to the latest post on New York vs. Bed Bugs, where Renee Corea gives the lowdown on the latest research from the University of Kentucky on pyrethroid resistance, which confirms that
knockdown resistance (kdr-type) mutations, conferring resistance to synthetic pyrethroid pesticides, are widely prevalent in U.S. bed bug populations. The study, forthcoming in Archives of Insect Biochemistry and Physiology, finds that one or two of two previously identified genetic mutations (briefly discussed here) are present in a majority of U.S. bed bug populations.
In particular, check out Renee’s illuminating discussion with the researchers, where Mike Potter cautions us not to throw the pyrethroid baby out with the bathwater:
I think it may be a bit too strong of a statement to conclude that pyrethroids “don’t work” on most of the bed bug populations in US, as we often do kill a percentage of the individuals we test in the laboratory, especially when they are contacted directly with the wet spray deposit. . . . Reports from many pest control firms further indicate the pyrethroid products are not performing as well as they would like.
The study by UK entomologists Mike Potter, Ken Haynes and Reddy Palli and Fang Zhu will be released in an upcoming issue of the Archives of Insect Physiology and Biochemistry.
Here’s a new story on this research from Pest Management Professional. It notes that alhough the study covers pyrethroid-resistant strains in the US,
Scientists in other countries have also found pyrethroid resistance in bed bugs on a smaller scale, so the resistance could be worldwide.
And provides some speculation on how this state of affairs may have come into being:
Potter said one of the reasons for the resistance could be that the bed bugs were previously exposed to pyrethroids before coming to the United States. Pyrethroids are used to combat many different insects and are used in mosquito bed nets to combat malaria.
Another possibility is the bugs developed resistance in the 1940s and 1950s when DDT was used for bed bug defense. Bugs that are resistant to DDT have the same target-site resistance as pyrethroids, Haynes said.