Backyard mosquito spray trees, but can be too deadly for insects, birds

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CASCADE TOWNSHIP, Michigan – It’s an increasingly familiar sight in American cities and suburbs: a van stops right up to the curb. Workers wearing gloves, masks and other protective equipment attach backpack-like mechanisms with plastic hoses, similar to leaf blowers.

Running the engines, they infuse trees, shrubs and even house walls with pesticides targeting an age-old threat: mosquitoes.

The spindly-legged winged leeches have long been the bane of backyard barbecues and, in tropical countries, carriers of serious disease. With climate change widening the insect’s range and extending its first season, more Americans are turning to the booming professional garden sprayer industry.

“If you like being outdoors, it’s definitely nicer not to kill mosquitoes and not worry about all the trouble,” said Marty Marino, a recent client in Michigan’s Cascade Township, a bedroom community near Grand Rapids.

But scientists are beginning to worry about the chemical bombardment that fears that overuse of pesticides harms pollinators and poses a growing threat to insects-eating birds.

“The materials these companies spray kill all insects,” said Lynn Goldman, a professor of environmental health at George Washington University and former assistant administrator for toxic substances at the U.S. Environmental Protection Agency.

“That includes bees, butterflies and all sorts of beneficial insects that people may not like but should,” Goldman said. “It’s not good to have this kind of random kill that ruins the whole ecosystem.”

According to the journal Biological Conservation, more than 40% of insect species worldwide are in danger of extinction, including some pollinators and butterflies.

Spray companies, proliferating with rising demand, say they are trying to minimize pollinator losses but recognize collateral damage.

Mosquito Joe, who covered Marino’s and several neighbors’ yards on a humid July morning, avoids spraying on windy days when poison would blow on flowering plants that attract bees, said Lou Schager, president of the company in Virginia Beach, Virginia. .

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

In 2020, the U.S. Centers for Disease Control and Prevention reported a “dramatic” increase in diseases spread by mosquitoes and other blood feeders. Zika, Chikungunya and West Nile viruses have surfaced in the US. And Asian tiger and yellow fever mosquitoes that originated in the tropics are now common in southern states and are beginning to hit Southern California.

Due to climate change, mosquito season in Michigan is about a month longer at the start and end than it was a few decades ago, as more and more types of warm weather emerge, said entomology professor Edward Walker of Michigan State University.

Meanwhile, mosquito repellent revenues have skyrocketed, according to a trade journal Pest Control Technology. Exterminators are adding mosquitoes to their traditional services and new companies are making mosquitoes their primary focus.

Total industry totals were not available. But more than 70% of the pest control companies surveyed last year offered the service, up from 38% in 2014. It generated nearly one-fifth of company revenues in 2021.

A Zika outbreak that began in 2015 and spread to more than 80 countries helped fuel growth in the company, said Daniel Markowski, technical advisor to the American Mosquito Control Association, a 1,200-member nonprofit.

“It was all over the media,” Markowski said, and “made a lot of pest control companies say, ‘Holy cow, I could make a lot of money from residential services.'”

Founded in 2010, Mosquito Joe now has 173 franchises in 39 states, Schager said.

Many companies use a “residual barrier” strategy, where pesticides are sprayed around the perimeter of a property, which usually takes several weeks. When mosquitoes settle on the bushes or trees, they receive a lethal dose.

For garden treatments, companies typically use pyrethrins — insecticidal compounds 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 indirectly harm birds by killing insects they feed on, Goldman said.

A drop-off of 3 billion North American birds over the past few decades, they were largely insectivores, from the whip-poor willow to redwing blackbirds and barn swallows.

EPA says it is seeking more information about pollinator damage as part of a periodic review of pyrethrins and pyrethroids and could order labeling changes if necessary.

Critics also argue that homeowners fall for corporate sales pitches when simpler methods, such as emptying stagnant water wells and running electric fans, would keep mosquitoes at bay.

The Mosquito Control Association says companies should clean up mosquito breeding areas first and spray only when an inspection shows it’s necessary, rather than on a set schedule.

“Once I do my job, you won’t need my mosquito service over time,” said Dan Killingsworth, director of operations for Environmental Security Pest Control, based in Panama City Beach, Florida. “If I can reduce mosquitoes on your property to where they are no longer a problem, we may be able to eliminate that service.”

Many companies don’t go that far, Markowski said. “They just come out, spray your property, and leave.”

Schager said his company limits the use of insecticides and usually sprays every three to four weeks, arguing that regular treatments are needed to disrupt breeding cycles.

Michigan homeowner Marino says he is 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. About 10% of Mosquito Joe’s customers use this option, although most prefer the longer-lasting pyrethroids, Price said.

The company charges about $90 per pyrethroid treatment, while oils cost about 20% more, he said.

“One of our dogs likes to eat wood chips from the landscape,” Marino said. “If there’s the synthetic insecticide on it, that’s a big concern.”

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