Bed bugs are hard to kill. Have you ever sprayed a can of pesticide on a bed bug only to see it crawl away unaffected? Millions of people have experienced the same feeling of helplessness after seeing that. What is it about bed bugs that makes them so impervious to certain pesticides? Let’s take a closer look and dig into how bed bugs resist chemicals.
The Rise and Fall of DDT
The timeline of bed bug resistance starts almost a century ago. During and after World War II, DDT became the insecticide of choice to deal with bed bug infestations. DDT was a powerful organophosphate that proved lethal to bed bugs of all ages and strains for many years. It’s credited with the near eradication of bed bugs in North America and most of Europe for decades.
Despite its infamous potency, not every bed bug exposed to DDT succumbed to it. Bed bugs have a short lifespan and can start breeding only weeks after birth. This allows them to mutate in an attempt to survive environmental changes. Some bed bugs that encountered DDT had mutations that allowed them to resist its toxins.
DDT likely wiped out all but the most resistant strains of bed bugs. The survivors were the ones that mutated and can completely resist chemicals like DDT. Their offspring then thrived with those powerful resistant properties intact.
After the US banned DDT use in the 1970s, the pest control industry moved on to weaker alternatives. By then, bed bugs had the genetic tools in place to build resistance to almost any synthetic insecticide they ran into. Modern bed bugs can secrete chemicals that digest poisons on their shell, rendering them harmless. They can even flush toxins from their internal organs using sophisticated biological pumps.
The New Bed Bug Resistance Toolbox
After decades of absence, bed bugs returned to the US in force over the last few years. It’s believed that all these modern bed bugs are completely resistant to DDT. The majority of active strains are also showing resistance to many modern pyrethroids. These insecticides had gained mainstream popularity in recent years, but we’ll need to address these new bed bugs in new ways.
The first key to dealing with the modern bed bug epidemic is understanding how bed bugs resist chemicals. That way, we can know how to wipe them out again. Researchers from Washington State University and the University of Kentucky stepped up to the plate. They conducted a four-year study that identified 14 unique bed bug genes. These genes appear to work to repel pyrethroids in common use today.
“Every living thing on Earth has a unique set of strategies to adapt to life-threatening situations in the environment,” said Zhu, the leader of the study. “The surprise discovery we never expected is that most of the genes responsible for the pesticide resistance in the bed bug are active in its outer skin-like shell or cuticle. This is the unique adaptation that has not been discovered in cockroaches, termites, ants, or other insects.”
The study’s co-author, University of Kentucky’s Subba Palli, believes that the solution lies in using RNA to interfere with these unique genetic functions. In laboratory settings, RNA strands can be injected directly into a bed bug. But this isn’t as simple a task with wild populations. We would need to develop a technology that can inject the RNA strands in a less direct way. Another option would be to alter a bed bug’s existing RNA to perform the same interference. “If someone solves that, I think we could have a really good product,” said Palli.
In the field, pest controllers are seeing pyrethroid resistance develop during treatments. When exposed to a single insecticide, infestations can begin showing resistance in just a couple of generations. Since bed bugs can hatch and mature in just three weeks, the timeline for resistance to show is very short.
Avoiding Bed Bug Resistance During Treatment
When addressing how bed bugs resist chemicals, there are two forms of resistance you’ll need to consider for your home treatment. The first is evolutionary resistance, which developed over decades. This long-term change has made certain chemicals ineffective for practical treatment. The other concern is short-term mutations, which can impact your follow-up treatments.
The first step is to make sure you’re not relying on a single chemical product to treat your home for bed bugs. Not only is it likely that the bed bugs in your home will resist chemicals they’re exposed to repeatedly, but it’s incredibly unlikely that you would be successful either way. Modern bed bug treatment strategies, like our 4-step solution, combine both chemical and non-chemical methods of attack. It’s also recommended that you use multiple contact and residual sprays to ensure that the infestation can’t mutate to resist chemicals they’ve been exposed to.
Just a few years ago, there was a wide range of chemical compounds on the market that were proven to kill bed bugs, either on contact or over time. Over the years, bed bug strains have developed resistances to many of these compounds, and those products are no longer as effective. To cut their losses in the development of these compounds, the manufacturers started selling to hardware stores and supermarkets at a discounted price.
Since these off-the-shelf sprays may not be able to curb your bed bug population, don’t use them! Instead, opt for newer contact and residual sprays that are effective against all strains of bed bugs. They may cost a bit more, but you will have peace of mind knowing that what you are applying is doing the job. We only carry the newest products with no known bed bug resistance.