Originally Published in PCT Magazine March 2016
They also examined a population of pyrethroid-resistant bed bugs in New Jersey that had not been exposed to neonics since they were collected in 2008.
The bed bugs from Harlan’s lab that never have been exposed to neonics died when they were exposed to a very small amount of the insecticide. The New Jersey bed bugs fared slightly better, showing moderate resistance to four different types of neonics.
But the bed bugs from Michigan and Cincinnati, which were collected after combinations of insecticides were introduced to the U.S., had much higher levels of resistance to neonics.
It only took 0.3 nanograms of a substance called acetamiprid to kill 50 percent of the nonresistant bed bugs from Harlan’s lab — but it took more than 10,000 nanograms to kill 50 percent of the Michigan and Cincinnati bed bugs.
Just 2.3 nanograms of another substance, imidacloprid, was enough to kill 50 percent of Harlan’s bed bugs, but it took 1,064 nanograms to kill the Michigan bed bugs and 365 nanograms to kill the Cincinnati bed bugs.
Compared with the Harlan control group, the Michigan bed bugs were 462 times more resistant to imidacloprid, 198 times more resistant to dinotefuran, 546 times more resistant to thiamethoxam, and 33,333 times more resistant to acetamiprid.
The Cincinnati bed bugs were 163 times more resistant to imidacloprid, 226 times more resistant to thiamethoxam, 358 times more resistant to dinotefuran, and 33,333 times more resistant to acetamiprid.
The researchers believe that the detection of neonicotinoid resistance in the New Jersey bed bugs, which were collected before the widespread use of neonics, could be due to pre-existing resistance mechanisms.
When exposed to insecticides, bed bugs produce “detoxifying enzymes” to counter them, and the researchers found that the levels of detoxifying enzymes in the New Jersey bed bugs were higher than those of the susceptible Harlan population.
“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,” said Anderson, who is also a researcher at the Fralin Life Science Institute.
“If resistance is detected, products with different modes of action need to be considered, along with the use of non-chemical methods,” said Romero.
LOOKING FOR NEW APPROACHES. Another researcher at Virginia Tech, Dr. Dini Miller, is also working on ways to tackle the bed bug issue.
Miller and her colleagues at the Virginia Tech Dodson Urban Pest Management Laboratory began investigating bed bugs in 2004 by studying pesticide resistance and new approaches to their control.
A large part of their work involves teaching people how to manage bed bug infestations in homes and businesses.
In addition, Miller works with home health care workers, social services, apartment and shelter managers, and school facilities personnel to raise awareness.
The preceding article was reprinted from materials provided by Virginia Tech University.
What I take away from this article is that heat will continue to become more and more of a primary treatment method for the extermination of bed bugs. You can find more about killing bed bugs with heat here.