DDT and bedbugs

Jake Young reports that bedbugs are back.

Andrew Bolt naturally blames greens: "Being green can make you itchy", because:

Before World War II, bedbug infestations were common in the U.S., but they were virtually eradicated through improvements in hygiene and the widespread use of DDT in the 1940s and 1950s...

Bolt thinks that the DDT ban in the US caused bedbugs to return. He's wrong, and it's the sort of mistake that people who don't believe in evolution make.

Here's what the World Health Organization says about bedbug control:

Houses with heavy infestations need to be treated with long-lasting residual insecticide. One treatment is normally sufficient to eliminate bedbugs but, if an infestation persists, re-treatments should be carried out at intervals of not less than two weeks. In many countries, resistance of bedbugs to DDT, lindane and dieldrin is common. The insecticide selected should thus be one known to be effective against the target population (see Table 4.1).

Table 4.1 lists thirteen insecticides that you could use. DDT isn't one of them because bedbugs have evolved resistance. In fact, DDT spraying seems to make bedbug infestations worse:

House spraying against malaria was very popular in many tropical countries, partly because it killed bedbugs. Unfortunately, the bugs quickly developed resistance to the insecticides, resulting in numerous complaints that spraying no longer controlled bedbugs, even though it still killed mosquitos.

Another possible explanation for the increase in the numbers of bedbugs observed is that the insecticide spray irritated the bugs, causing them to leave their hiding places. Seeing many more bedbugs than before, people believed that spraying caused an increase in the bug population (7, 8).

As a result, many householders refused malaria spraying teams access to their homes. It is possible that in some areas the occurrence of bedbugs contributed indirectly to the ineffectiveness of malaria control programmes.

Christopher Curtis, Professor of Professor of Medical Entomology at the London School of Hygiene & Tropical Medicine adds this:

Numerous studies with pyrethroids on bednets or used for house spraying have shown high mortality of nuisance insects such as bedbugs, whereas with DDT these are poorly killed (or even stimulated to cause extra biting nuisance). This suppression of nuisance, together with the lack of a visible deposit on walls, have led to better acceptance of pyrethroid applications by householders (and hence higher coverage rates) than with DDT. This is probably a major reason for the better malaria control achieved with pyrethroids.

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There was a blurb on the news last night--I think they mentioned a possibility that I believe needs consideration, namely, that the apparent increase in US bugs may be due to travellers bringing them back from abroad. That idea was discussed on the radio, I think, some months ago.

Tim. You make an excellent point that is true about insect control in general:

The particular method should be tailored to the particular problem (ie, to the target insect population and to the details of the infestation).

Why this basic point is so hard for some to grasp is a mystery.

Base on past experience, it should be no surprise that there is no silver bullet when it comes to insect control and even if there were for a short time, it would not last (as a result of development of resistance to the particular chemical).

The most effective methods are those that are selected for their specificity with regard to the target insect popluation and carefully controlled to minimize the development of resistance.

A large number of insecticides and other insect control methods (includuing biological controls) has been developed in the 60 years since DDT came into use -- many of which do not have the tendency to be concentrated in tissue over time.

With so many wepons in one's arsenal, it simply makes no sense not to choose the one that is best suited to the purpose -- and that will casue the least amout of collaterall damage on the environment.

You know, when my dog got fleas quite a while back, the spray that we used was some hormone that prevented the juveniles from maturing into adults. That is, it was quite specific to the flea, and was something that they (or other insects) were unlikely to develop resistance to.

I don't see why something similar could not be done with bedbugs.

JB:

Why this basic point is so hard for some to grasp is a mystery.

Nah, no mystery.

Ideologue Googlers know nothing about the subject, but that doesn't stop the opining.

Best,

D

You are probably right about the "Ideologue Googlers" ( "Googleologues"?)

Then again, at least some of the people who keep bringing up the DDT issue are undoubtedly smart enough to understand the issue -- and dishonest enough to misrepresent the truth.

If such people spent half as much time working on real solutions to problems as they do writing position papers to confuse people about science, they might make a valuable contribution to society every now and then.

"Then again, at least some of the people who keep bringing up the DDT issue are undoubtedly smart enough to understand the issue -- and dishonest enough to misrepresent the truth."

Not necessarily. A great deal of rightwingitude appears to consist of manually turning down the wattage on one's brain so that one does not have to say something one knows is obviously wrong. The anthropogenic climate change "debate" being the ultimate collection of such.

On a positive and proactive note:
There is a US and International web site http://www.QRegistry.org for business travelers and vacationers. They are listing hotels, motels, vacation properties ... who are proactive in an effort to avoid bed bug and pest infestation. From the backpacker motel to five stars; each room indexed must be verified as having good pest control practices administered by a professional licensed service and training programs for inclusion. They present your complaint of infestation to the property owners as well as the appropriate health agency for further investigation and extermination..