Pesticide Resistance and Exterminator Practice

Back in 2008 a single course of Permethrin, mixed at label rates and applied as per label directions, could get rid of bed bugs in a single treatment. Sometimes I would treat a baseboard and find dead bed bugs less than 18 inches from the baseboard. The resistant ones made it a few feet. Over the years I saw fewer and fewer dead bugs meaning they survived. Today it is normal for me to see live bugs harbouring on surfaces that have been treated. I hate seeing that.

In one particular case I took 12 bugs from an infested suite and placed them in a teflon pan treated with Cyfluthrin at max label rate and 9 of 12 bugs were in perfect health after 24 hours of full time contact. The only sign of the bug’s discomfort was they refused to aggregate like they would on an untreated pan – the same pattern I see in the field. Given the bugs exposure to the chemicals in the field would be measured in minutes or seconds I fail to see how that kill anything.

I get around this problem by using modified glue boards on all my chemically treated suites. I chemically chase the bugs out of their harbourages and I catch them in the traps. If I can hit the bugs directly I think I can usually kill them but in some cases I am starting to wonder about that as well. Sometimes I spray a bug directly and they don’t even arch their backs (stilting) in discomfort. Does not inspire confidence.

If it were not for glue boards I would have given up long ago. In fact, I have no idea how my competitors actually kill bed bugs with these chemicals – certainly, as an exterminator with almost 10 years experience specializing in bed bugs, I can’t do that. And I take an hour to treat each suite and I still can’t get them all. I have actually worn out 9 spraying wands where the cable carves a groove into the brass handle of my B&G sprayer causing leaks. I showed my chemical supplier these worn out wands and he was mystified – no one else ever wears out their wands like that.

But some exterminators in my area still regularly treat entire apartments once a month with 10 minute treatments and they are at times successful. Remarkable. How is this possible? Are these exterminators just that much better than me that they can kill all the bugs in 10 minutes while I fail in an hour? Actually I have some evidence to the contrary.

In the resistant case mentioned above (bugs could not be killed in 24 hours of full time contact) the history included 2.5 years of unsuccessful 10 minute chemical treatments done by others and upon initial inspection the suite was loaded with live crawling bugs. The regular exterminator continued with regular treatments while I added the glue boards to the protocol and collected 14400 bugs. At one point 4 hours after treatment I entered the suite and found a climb up interceptor (screwed on top of a glue board contraption) filled with liquid. I retrieved the chemical sample and had it analyzed in a lab and it was found to be “a “witches brew” of unidentified chemicals but mostly “Lambda-cyhalothrin.” Lamdacy is on label for crack and crevice use only. It is impossible to even inadvertently fill an interceptor with chemical using crack and crevice techniques. In other words the exterminator was applying chemicals illegally. I wonder if illegal methods played a role in the successful 10 minute treatments in the other suites?

I have noted numerous other similar cases. In one instance I was asked to comment on the exterminator staining a customer’s hardwood floor in the middle of the kitchen. It had appeared that chemical had spilled and caused an oily looking stain. In the thousands of suites I have treated I have never stained a hardwood floor because everything I am allowed to use is water based. You don’t get oily stains using water based chemicals.

In another case I noted the previous exterminator managed to peel the finish off the hardwood floor beside the baseboard. I have never done that – ever. I have no idea what kind of chemical would cause that.

In other cases I inspected a job another exterminator had done and found the floor was puddled with chemical a day after treatment. And the room smelled exactly like Propoxur which is illegal for bed bugs. And Propoxur is oil based so it made sense that the puddles remained for 24 hours. Typical water based (legal) treatments dry in 1 or 2 hours.

Many times customers will ask me why my treatments have no odour like the last exterminator’s treatment. There are no chemicals I can legally use that cause smells.

Given the resistance profiles I see in the field it is impossible to successfully chemically treat suites in ten minutes. I know for a fact if I tried that I would fail every time. In fact I can spend an hour carefully going through the suite and I would still fail without glue boards added to the protocol. So perhaps illegal use of chemicals might account for some of the success exterminators have with quick chemical only treatments.

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