Mosquito spraying booms, but may be too deadly

It’s an increasingly familiar sight in U.S. cities and suburbs: Workers spraying yards for mosquitoes

The winged, spindly-legged bloodsuckers long have been the bane of backyard barbecues and, in tropical nations, carriers of serious disease.

Now, with climate change widening the insect’s range and lengthening its prime season, more Americans are resorting to the booming industry of professional yard spraying.

“If you like to be outside, it certainly makes it more pleasant not to be swatting mosquitoes and worrying about all the issues,” said Marty Marino, a customer in Michigan’s Cascade Township, a bedroom community near Grand Rapids.

However, the chemical bombardment is beginning to worry scientists who fear over-use of pesticides is harming pollinators and worsening a growing threat to birds that eat insects.

According to the journal Biological Conservation, more than 40% of insect species worldwide are threatened with extinction, including some pollinator bees and butterflies.

Spraying companies, which have been multiplying with the surging demand, say they try to minimize pollinator losses but acknowledge there’s collateral damage.

Mosquito Joe, which treated Marino’s yard and those of several neighbors on a humid July morning, says it avoids spraying on windy days when poisons would blow onto flowering plants that attract bees.

“We need our pollinators,” said David Price, the company’s director of technical services. “They’re incredibly important. But, at the same time, we need to eliminate mosquitoes that (carry) diseases.”

In 2020, the U.S. Centers for Disease Control and Prevention reported “dramatic” increases in illnesses spread by mosquitoes and other blood feeders. Zika, Chikungunya and West Nile viruses have turned up in the U.S. And Asian tiger and yellow fever types of mosquitoes that originated in the tropics are now common in Southern states and have begun afflicting Southern California.

With climate change, experts say Michigan’s mosquito season is about a month longer at the beginning and the end than a few decades ago, as warm-weather varieties increasingly turn up.

Meanwhile, according to Pest Control Technology, a trade publication, the revenue from mosquito spraying has soared. Exterminators are adding mosquitoes to their traditional services, and new companies are making mosquitoes their primary focus.

Established in 2010, Mosquito Joe says it now has 173 franchises in 39 states.

Many companies use a “residual barrier” strategy, spraying pesticide around the perimeter of a property that typically lasts several weeks. When mosquitoes settle on the bushes or trees, they get a lethal dose.

For yard treatments, companies typically use pyrethrins — bug-killing substances produced by chrysanthemum flowers — or synthetic imitators called pyrethroids.

The federal government says the chemicals are safe for humans when used as directed and mostly nontoxic to birds. But they’re deadly to fish and bees, and harm birds indirectly by killing insects on which they feed.

Critics contend homeowners are falling for company sales pitches when simpler methods, such as emptying stagnant water sources and running electric fans, would keep mosquitoes away.

The mosquito control association says companies first should clear out mosquito breeding areas and spray only when an inspection shows it’s needed, instead of on a set schedule.

Marino says he’s trying an optional spray of water mixed with “essential oils” from plants such as garlic, lemongrass, peppermint and rosemary, which are less harmful to other insects.

“One of our dogs likes to eat wood chips from the landscaping,” Marino said.

“If he’s going to do that and there’s the synthetic insecticide on it, that’s a great concern,” he said.