Ultrasonic Pest Control Devices - November 5, 2008
Jeff Schalau, Associate Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County

When it comes to pest control, most people want to do the right thing. That is, to prevent or minimize pest damage to plants, textiles, wood and/or stored food while causing the least disruption to natural systems we collectively call “the environment.” Furthermore, people are increasingly looking for pest management solutions that use little or no pesticides. In general, this is also a good idea. Although many pesticides are becoming safer, people are increasingly drawn toward non-pesticide alternatives.

Ultrasonic pest control devices are commonly marketed as an alternative to pesticides. These devices claim to use ultra-high frequency sound waves to chase away birds, bats, rodents and arthropod pests like fleas, cockroaches, silverfish and even spiders. Most of them are designed to plug into an electrical outlet. The devices are usually a little plastic box with a handy LED light to tell the owner it is on and working. Some ultrasonic devices are battery-operated for such applications as a flea-repellent collar and pocket-sized cards for outdoor enthusiasts to repel mosquitoes.

Several researchers have concluded that ultrasonic devices do not effectively repel or eliminate pests from homes and/or gardens. In fact, in the 1980's the Federal Trade Commission charged several companies with false advertising and required them to make refunds to customers. Today, similar devices are still being sold. More often than not, these devices are not supported by any form of scientific research proving their efficacy.

Most insects and animals hear or feel the same range of frequencies that humans do. If a sound or frequency doesn't bother us, it is doubtful that it will bother pests. Animals placed in cages next to these devices continue to live normal lives. If they are paired with the opposite sex, the animals continue to reproduce. Others have placed ultrasonic devices in rat and bat infested attics and found that pest populations continue to live and reproduce in those attics.

“New and improved” subsonic devices have recently hit the market. Manufacturers claim they are even better than ultrasonic ones. Instead of sending out a high frequency signal, they produce a low frequency sound or vibration. Some producers of subsonic devices say they use the electrical wiring in a house or structure to form a protective shield around the inhabitants and the things they want to protect. The box, plugged into a common outlet, supposedly sets up low frequency vibrations through the electrical wires that pests can’t stand. Again, researchers have proven subsonic devices do not work.

As noted above, people are usually purchasing these devices to discourage small rodents, bats, insects, or spiders. There are several strategies that do work on these and other pest species. For any pest, try to remove any attractant (food, water, nesting material, etc.) and keep areas as clean as possible. In addition, seal cracks and crevices around doors, windows, and utilities; eliminate weedy growth or vegetation near the house; use traps and/or glueboards inside the house; seal food (including pet food) in pest-proof containers; and monitor closely to determine if additional measures are warranted.

For reliable pest management, learn and follow integrated pest management (IPM) guidelines. These are: correctly identify the pest species, learn about that organism’s behavior and biology, employ preventative strategies, apply direct control strategies if needed (traps, baits, pesticides), and finally, monitor the effectiveness of your efforts and revise as necessary.

Years ago, I was at my mom’s house and noticed an ultrasonic device plugged into a wall socket near the dining room table. I could also hear a slightly audible, high frequency noise. Again, I found it annoying, but it was not enough to prevent me from enjoying dinner that night. If it had worked on me, millions of other Americans could have taken advantage of a new weight loss product. That just goes to show if it sounds too good to be true, it usually is!

The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at cottonwoodmg@yahoo.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.

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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: October 30, 2008
Content Questions/Comments: jschalau@ag.arizona.edu
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