Floral-Scented Pesticide Lures Mosquitoes to Their Death

There are those who argue that mosquitoes serve a purpose, that their droning, blood-gorging presence represents an important link in a fragile food chain. Then there's Agenor Mafra-Neto, who mostly just wants them to die. The chemical ecologist and his colleagues presented their new strategy for mosquito control at the 254th National Meeting & Exposition of the American Chemical Society.

Irritating though they are, mosquitoes are much more than just pests; they're also vectors of deadly diseases that claim millions of lives every year. While some scientists race to develop and administer vaccines against these viruses, others are tackling the problem from the other end, hoping to block the bloodsuckers before they ever pierce a person's skin.

Today's most common chemical mosquito-protection measures are effective, but nonspecific. The same insecticide that takes out a mosquito can kill a bee or poison a dog or a baby. Pesticide runoff can contaminate the water supply. It also can't eliminate all the mosquitoes, and the survivors reproduce, thereby increasing their resistance to the chemicals.

In other words: There's room for improvement. So Mafra-Neto, founder of the pest management laboratory ISCA Technologies, teamed up with researchers from other universities to create something better.

First, they gathered piles of mosquitoes' favorite nectar-producing plants and analyzed the chemical makeup of each flower's fragrance. They exposed mosquitoes to individual elements of each fragrance to find out which ones got their attention, then eliminated any scent that also brought bees to the yard. The final result was an intoxicating perfume of sugars and proteins that no mosquito could refuse.

The researchers mixed this special blend with a highly concentrated, slow-release pesticide called Vectrax, which can be sprayed or spread onto plants and buildings. The pesticide solidifies in teeny droplets and will not spread to other surfaces, but it will spread in the bodies of the mosquitoes who come to taste it.

And taste it they do.

"The blend of chemicals that we use to attract mosquitoes is so powerful that they will ignore natural plant odors and attractants in order to get to our formulation," Mafra-Neto said in a statement. "From a mosquito's point of view, it's like having an irresistible chocolate shop on every corner. The product is so seductive that they will feed on it almost exclusively, even when it contains lethal doses of insecticide."

Mafra-Neto and his colleagues are currently conducting field tests in malaria-vulnerable villages of Tanzania. Their early results suggest that their product can cut mosquito populations by two-thirds in the first two weeks alone, and may be able to eliminate the pests entirely. Mafra-Neto wouldn't be sorry to see them go.

"I truly hate mosquitoes and ticks," he says. "Imagine: Maybe one day we will be able to go into our backyards or parks and not have to worry about being bothered by either of them."