An electronic bug zapper is a great tool for ridding yourself of pesky flying insects. It emits a light that attracts flying insects to it, where it zaps or kills them with an electric shock. However, there is a bit of controversy surrounding the effective use of bug zappers, when used as a repellent for biting insects.
Electronic insect zappers are non-discriminate killers. Since most insects are attracted to a light, the device will kill anything that enters, regardless of what species it is. Therefore, the zapper will get all types, as well as any beneficial flying insects that prey on other bugs that you don't want around. A 1996 study conducted by the University of Delaware collected insects killed in six separate zappers, finding that only a small portion killed were biting or harmful insects such as mosquitoes, flies and gnats. In fact, there were more non-biting species killed by bug zappers such as fireflies and beetles.
Why Not Mosquitoes?
The study points to an ineffectiveness in luring mosquitoes, the number one biting foe of humans and pets. Rather than being attracted to a bug zapper's light, mosquitoes are drawn to the carbon dioxide it emits, which is a more powerful lure to biting insects than light. The study points out that the use of bug zappers can help against biting insects since the light may, indeed, draw them from far off. However, any humans nearby will become the focal point that then attracts the biting insect. In other words, a bug zapper can help a biting insect hone in on its human prey, rather than eliminating the pest.
Since the University of Delaware study was released more than 10 years ago, manufacturers of bug zapping devices have tried to adapt to the criticism by making improvements to the devices. Manufacturers have added Octenol, which is a non-toxic element emitted by the zapper, to attract mosquitoes. This is a pesticide–free substance that the manufacturers claim outweighs any carbon dioxide attraction, thus making the device more effective for mosquito control. Since mosquitoes are attracted to the carbon dioxide emitted by both human breath and sweat, newer models of mosquito electronic zappers attempt to take advantage of this relationship by imitating this carbon dioxide expulsion.
Alternatives to Zappers
There is a device on the market that does not zap flying insects that respond to carbon dioxide attraction. It emits a steady stream of carbon dioxide with an Octenol attractant. Mosquitoes that get attracted to the mix get caught in a net where they will dehydrate and die. The University of Delaware study offered a simple alternative for repelling biting insects when humans gather on a warm summer night outdoors. The study suggests using a box fan that blows across the area where people gather, because mosquitoes cannot easily fly in a wind that flows more than 1 mph. Although documentation questions bug zapper effectiveness and the Environmental Control Agency claims there is no significant scientific evidence proving their effectiveness, the device remains a best seller on the pest control market.