Electronic Pest Control Devices

Electronic Pest Control Devices

Numerous electronic pest control devices are readily available in Alaska and just about every where. They are advertised on late night television “infomercials”, through mail order catalogs, and on the internet. Hardware stores and garden centers usually stock some sort of electronic device advertised to repel a variety of pests. Although these devices have been around for at least 20 years, they have only recently become popular and widely advertised, probably due to their environmentally friendly claims. There is a wide range of opinion about these devices, some people claim that they work for them, others claim they are not effective at all. While electronic pest control devices remain a controversial topic, there has never been any scientific evidence proving them as effective. Since these devices are not regulated under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the EPA does not require the same kind of efficacy testing that it does for chemical pesticides. Adequate testing for adverse health effects as well as performance data for these devices are seriously lacking.

Types of Devices
There are basically two types of electronic pest control devices widely available, these are Ultrasonic and Electromagnetic.

 

Ultrasonic devices operate by emitting short wavelength, high frequency sound waves too high in pitch to be heard by the human ear ? that is, all frequencies greater than 20,000 Hz. Humans can hear frequencies from 20 to 20,000 Hz but as we age, we become less sensitive to the higher frequencies. (Long wavelength, low frequencies ? below 20 Hz ? are called infrasound and are also inaudible to humans.) Although it’s implied that ultrasound has special properties that make it more repellent than audible sound, there’s no evidence to support this.

 

We can’t hear ultrasound because our eardrums can’t vibrate fast enough, but some animals such as dogs, bats and rodents can hear well into the ultrasonic range. Some insects, such as grasshoppers and locusts can detect frequencies from 50,000Hz to 100,000 Hz, and moths and lacewings can detect ultrasounds as high as 240,000 Hz produced by insect-hunting bats.

 

Insects detect sound by special hairs or sensilla located on the antennae (mosquitoes) or genitalia (cockroaches), or by more complicated tympanal organs (grasshoppers, locusts, moths and butterflies).

 

But just because they can detect ultrasonic waves doesn’t mean that they’re controlled or repelled by it.

 

Cockroaches, for instance, initially respond by moving about a bit more than usual, but don’t appear overly eager to escape from the sound waves. This includes devices that emit uniform frequency as well as changing frequencies of ultrasound. Rodents adjust to the ultrasound (or any new sound) and eventually ignore it. At best, ultrasonic waves have only a partial or temporary effect on rodents. Numerous studies have rejected ultrasonic sound as a practical means of rodent control.

 

Ultrasound has not been shown to drive rodents from buildings or areas, nor has it been proven to cause above normal mortality in rodent populations. Some people that have used them claim that they work for them, so we cannot rightfully say that should never be used, but the evidence points toward these devices not being worth the money, time or effort.

 

Tests of commercial ultrasonic devices have indicated that rodents may be repelled from the immediate area of the ultrasound device for a few minutes to a few days, but they will nearly always return and resume normal activities. Other tests have shown that the degree of repellence depends on the frequency, intensity, and the pre-existing condition of the rodent infestation. The intensity of such sounds must be so great that damage to humans or domestic animals would also be likely. Commercial ultrasonic pest control devices do not produce sounds of such intensity.

 

Electromagnetic pest repelling devices claim to alter the electromagnetic (EM) field of your household wiring to turn your whole home into a giant pest repeller, driving all pests out of the walls of your home. One such device called Pest Offense® is widely advertised on late night television using pseudoscientific jargon and scare tactics, such as reading the warning labels from pesticide containers which were obviously selected from agricultural chemicals, not household pesticides available to the general public.

 

Electromagnetic fields are present in every appliance that operates on electricity. When an appliance is switched on, a very weak electromagnetic (EM) field develops around the current-carrying wiring in your home.

 

An Australian test lab looked at the electronics of one of these devices. When plugged in, it generates a pulse in the electrical current (which also makes the little indicator light switch on and off). This causes the electrical current in the house wiring to fluctuate, which in turn makes the EM field fluctuate. This supposedly creates an intolerable environment for the pests.

 

However, this device draws only a very small amount of current compared to normal household appliances. Even an incandescent light bulb draws considerably more current than the pest device. This means that the EM field strength generated by the device is very small even when compared to a light bulb.

 

One has to wonder whether insects and rodents can even detect these low level EM fields. Supposedly, it’s the fluctuations in the current that drives out these pests but if they can’t detect the low level EM field then they couldn’t possibly detect the fluctuations, and even if they could, one needs to question whether or not they are repelled by them.

 

Scientific Evidence
We searched the peer-reviewed scientific literature and found no scientific test data or University tests giving any evidence that these devices actually operate as advertised. According to the National Coalition Against the Misuse of Pesticides (NCAMP), Dr. William B. Jackson, of Bowling Green State University conducted several tests of an Ultrasonic device called Pest Patrol®. These tests reportedly showed a “statistically significant decrease in mouse activity in two of the [Pest Patrol®] chambers.” However, we cannot verify this information since, when contacted Dr. Jacksons’ office referred us to an attorney. At the time of this writing, the manufacturers of the Pest Patrol® (Lentek International) are in litigation with the FTC regarding alleged false advertising cliams about their devices. (see: FTC Charges Lentek with making false claims)

 

We contacted several major manufacturers of the devices available locally in Alaska for scientific data to back up their product’s claims. None of those contacted would (or could) provide us with any useful test data. One of the manufacturers claimed they had the data, but “misplaced it”. The one manufacturer that did supply us with data submitted physical test data, that is, they provided frequency ranges, wattage usage rates, fire safety test data, and customer testimonials, but no scientifically proven pest repellent efficacy test data. In light of this lack of evidence, we decided to conduct our own field test.

 

We purchased several of the devices available in local Alaska hardware stores and garden centers. We spent an average of $19.00 per device, with prices ranging from $4.99 to $35.99.  Each device we tested were advertised to repel insects and rodents. We placed them in Alaska homes, restaurant kitchens, and warehouses, where known insect or rodent infestations existed. We installed the devices according to the manufacturers directions. We allowed the devices to work for a minimum of 3 days, and a maximum of one month. During this time we took glue trap counts daily to monitor actual insect and rodent populations and compared them to the numbers of these pests caught before the devices were plugged in. In all cases average trap counts after the devices had been in operation did not deviate significantly from average trap counts taken before the devices were installed.

 

Conclusions
There is no electronic pest control device, either ultrasonic, electromagnetic, or any combination of these, scientifically proven to repel, mitigate, irritate, kill, or otherwise effect any animal or insect to any degree that would be effective enough to justify their use. Rodents may be temporarily repelled, but they simply avoid the sound by going behind objects that deflect it. Eventually, says the Federal Trade Commission the rodents get used to it.

 

Pets can hear the ultrasonic devices and a study done by the Purdue University Veterinary School found the devices cause hearing loss in dogs and cats.

 

Some gadgets claim to create an ”electromagnetic field” to repel pests, these devices do not produce a field of such intensity required to have any effect. There is no scientific evidence that any of these devices will work.

 

Ultrasound has not been shown to drive rodents from buildings or areas, nor has it been proven to cause above normal mortality in rodent populations. Some people that have used them claim that they work for them, so we cannot rightfully say that should never be used, but the evidence points toward these devices not being worth the money, time or effort.

 

Tests of commercial ultrasonic devices have indicated that rodents may be repelled from the immediate area of the ultrasound device for a few minutes to a few days, but they will nearly always return and resume normal activities. Other tests have shown that the degree of repellency depends on the frequency, intensity, and the pre-existing condition of the rodent infestation. The intensity of such sounds must be so great that damage to humans or domestic animals would also be likely. Commercial ultrasonic pest control devices do not produce sounds of such intensity.

 

Since these devices are often expensive and of questionable effectiveness, they cannot be recommended as a solution to rodent or insect problems.

 

FTC Cracks Down on Manufacturers
In May 2001, the Federal Trade Commission sent warning letters to 60 companies selling these devices warning them not to make claims without scientific evidence. see: http://www.ftc.gov/opa/2001/05/fyi0128.htm

 

In August of 2002, the FTC has charged Lentek International with making false claims that their electronic mosquito repellent devices repel mosquitoes. see: http://www.ftc.gov/opa/2002/08/lentek.htm
 
Sources: National Coalition Against the Misuse of Pesticides. Pesticides and You”, Volume 22, Number 2, Fall 2002, page 2.
Federal Trade Commission. News Releases, www.ftc.gov
Consumers Choice, Australian Consumers Group www.choice.com.au.

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