The Real.Est List
Bedbugged! Bring back DDT! (Not!) What will, and won't, kill the critters
Bedbugged! is a weekly column by journalist and bed bug survivor Theresa Braine. For more, click here.
As bed bugs have encroached, and people cast about ever more desperately for ways to eradicate them, the cry of “Bring back DDT!” has risen.
It’s understandable. As I noted a few weeks ago, these creatures can drive you to strange, risky deeds. The thing is, DDT will not provide the answer. It will only kill more birds.
Mind you, the argument is twofold. There are those who insist that DDT never should have been banned, that its use should have been modified and more closely regulated instead. It’s not the DDT that was the environmental problem, they say. It was the overuse of it, the drenching of entire residences and fields and what have you, that caused the damage.
This may or may not be true. The issue concerning us now is whether bringing DDT back would eradicate the bed-bug problem. The answer to that is “No."
Many people don’t realize that DDT probably doesn’t work against bed bugs. Yes, DDT is what got rid of the things in the ’40s and ’50s, before being banned years later because of environmental concerns. But even then, bed bugs and many other insects were showing resistance to it.
Pesticide resistance is fairly common, and not just with bed bugs. It's an evolutionary tactic employed by every insect, said Tim Wong, director of M&M Pest Control, “since the beginning of time.”
To make modern matters worse, DDT acts on the same areas of a bug’s nervous system as do pyrethrums, which form the basis of many bed bug insecticides. So the buildup of resistance to DDT has paved the way for faster building of resistance to current pesticides made of pyrethrins (naturally occurring in a chrysanthemum species) and pyrethroids (synthetic chemicals derived from pyrethrins; the umbrella term for both is pyrethrums), according to the website Understanding Evolution, out of the University of California at Berkeley.
I say “resistant” and not “immune” because the bugs will die from pyrethrums if you dump enough on them. But they will probably not stick around long enough for that to happen, and the ones that live will give birth to babies that need a higher dose to die (which is how we got into the pesticide-resistance game to begin with). It is not unlike the advent of antibiotic-resistant microbes.
Partly because of this, a large percentage of bed bug populations, especially in New York, have become resistant to pyrethrin-based insecticides. What they may do when sprayed solely with these substances is to disperse rather than die, spreading the problem.
This is why a number of pesticides and other methods are deployed in a multi-pronged approach. Diatomaceous earth (DE), for example, is often used with a combination of other chemicals, one of those being a pyrethrum-derived insecticide. As Wong points out, DE is a mechanical killer, so there is no resistance to build; on the downside, it takes longer to kill a bed bug.
Another problem contributing to pesticide resistance is their overuse and misuse. You will recall Bobby’s complete dousing of my bedroom with enough Drione to make Wong tell me not to live there until I could clean it up. The problem being that bugs will know to avoid the pesticide and because the children of any bugs that live through the onslaught may very well be resistant.
Of course, if your chemical treatments don’t work, don’t immediately blame pesticide resistance. Inadequate prep, excess clutter and other impediments can also interfere in the killing process.
As bed-bug researcher Alvaro Romero told the website New York vs. Bed Bugs in 2009, excessive clutter might give bed bugs enough places to hide so that they can avoid the pesticides entirely.
“Thus, treatment failure is not always synonymous with insecticide resistance,” he said. “It is difficult to pinpoint when resistance begins. However, pest managers might suspect resistance when bugs persist in areas that they know were thoroughly and previously treated with insecticide.”