Are Bug Zappers Really Effective Against Mosquitoes? The Answer May Surprise You

Bug zappers kill bugs by the thousands. But there’s a problem: They kill the wrong bugs. They are ineffective against mosquitoes and other biting flies, and their otherwise indiscriminate killing can disrupt pollination and generally throw the environment out of balance. Plus, the force of their electrocution can spew a mist of disease-ridden bug parts out into the air. All of the mosquito experts we spoke with and every relevant university extension office we could find unanimously condemned bug zappers. To keep an area free of bugs or to prevent yourself from getting bitten, there are much better alternatives.

Why you should trust us

To learn more about bug zappers, we spoke to Laurence Zwiebel, PhD, a professor of biological science and pharmacology at Vanderbilt University. Zwiebel has been studying insect behavior for almost 40 years, and he’s been focusing on mosquitoes for the past 25, specifically looking at how olfaction—the sense of smell—drives mosquito behavior.

We also corresponded with Leslie Vosshall, PhD, a professor of neurobiology at the Rockefeller University. Vosshall has been studying insects for 30 years, with a focus on mosquitoes and repellency for the past 15 years.

Professor Jonathan Day of the University of Florida also shared his expertise with us. He has a PhD in medical entomology and has been studying mosquitoes and other bugs for nearly 40 years. He specializes in mosquito control.

We talked to Brian Provost, international sales representative and customer service manager of Flowtron, a leading manufacturer of bug zappers, to hear his perspective on the devices’ benefits and to address the common criticisms.

Additionally, we read as much as we could about bug zappers, immersing ourselves in academic studies and looking at a wide variety of university publications, many from extension offices.

Personally, I’ve written quite a bit about insect control, including guides to bug repellents, mosquito-control gear, fly swatters, and ant killers and an analysis of why you should steer clear of essential oil bug repellents. In writing and researching these articles, I’ve spoken to a wide variety of academics, product manufacturers, the Environmental Protection Agency, and Joe Conlon, technical adviser of the American Mosquito Control Association. I also keep honey bees, which makes me a little more in tune with pollination and the insect world.

Bug zappers kill the wrong bugs

Bug zappers work by emitting a UV light that attracts bugs to the center of the device, where they’re electrocuted, usually between two metal grids. Because of the irresistible lure of their light, bug zappers are incredibly effective at killing bugs. The only problem: They aren’t killing the bugs that bother you.

“Bug zappers are good for attracting insects that are attracted to bug zappers,” Leslie Vosshall, a neurobiology professor at the Rockefeller University, told us. This often doesn’t include mosquitoes or any other biting insects. A study from the University of Delaware tracked six residential bug zappers over a 10-week period and found that of the 13,789 insects killed, only 31 were biting flies (including mosquitoes). That’s a sad 0.22 percent. Given this, it’s no shock that the authors of the study concluded that bug zappers are “worthless for biting fly reduction.” In a similar vein, the American Mosquito Control Association notes that Notre Dame researchers conducted two studies on bug zappers (neither of which is online) and found that “mosquitoes comprised merely 4.1% and 6.4%, respectively, of the daily catch over an entire season.” As the Colorado State University Extension puts it, “No controlled scientific study has shown that these devices reduce mosquito biting rates outdoors.”

Pretty bad, right? Well it gets worse once you begin to understand which bugs are getting killed. According to the Delaware study, the zapped bugs include “many thousands of nontarget insects representing a rich taxonomic diversity.” This unfocused insect elimination is so extreme that, according to the authors of the University of Delaware study, “Even if targeted biting flies were effectively controlled by electric zappers, the resulting destruction of thousands of parasitoids, predators, aquatic insects, and other members of the nocturnally active fauna would be difficult to justify.” University of Florida professor Jonathan Day told us, “We’re in a big enough crisis with colony collapse with honey bees that I think anything that impacts a beneficial insect population is problematic.”

The ripple effect of this wholesale bug eradication hasn’t been fully explored. But with the possibility of bug zappers creating voids in the food chain, the authors of the University of Delaware study express concern for bats and nighthawks, both of which survive by eating insects nocturnally.