Yuen: The truth about mosquitoes — and what you may be doing wrong

The start of July typically marks the peak of mosquito season in Minnesota. You know what to do. Stock up on citronella candles, wear garlic around your neck, scare them with direct sunlight, stake ’em in the heart, and whatever you do, never invite a mosquito into your home.

Where was I? Oh, yes, distilling fact from fiction about how to ward off our favorite seasonal nuisance.

Mosquitoes weren’t even on my mind this year until Memorial Day weekend, and a trip Up North to a friend’s cabin. I do not exaggerate when I say hundreds of these bloodsuckers swarmed the head of my slow-moving 5-year-old, his pudgy cheeks rendered helpless as he tried to shield them with his fists. Later while our families were crowding into the minivan, our normally outdoorsy kids screamed bloody murder for my friend to hit the gas so we could escape the biblical-scale infestation.

We learned from the locals that the mosquitoes had hatched just a few days prior to our arrival. My friend said this year’s crop was the worst she’s ever witnessed at the cabin.

But what really works — and what doesn’t — to protect yourself from this summer’s onslaught? I contacted two myth-busters on this topic: Alex Carlson, spokesperson for the Metropolitan Mosquito Control District, and Matt Aliota, a vector biologist whose lab at the University of Minnesota studies the interaction between viruses and mosquitoes.

Is it really a bad year for mosquitoes?

“For lot of people, it feels like this year is a lot worse,” Carlson said, who says on average the levels are similar to those seen in 2019 and 2020. “Last year, there were almost no mosquitoes for pretty much the duration of the entire summer because of the drought.”

That said, some pockets of the metro area, such as northern Anoka County, or along the Mississippi and Minnesota rivers, are experiencing above-average mosquito populations this year because of heavier rain or higher water levels, he added. So if you live in a part of the state that has been wetter than usual, it could be that the mosquitoes are indeed back with a vengeance.

What the heck happened Memorial Day weekend?

The cold spring delayed the start of mosquito season. But after it warmed up, the mosquitoes that were waiting to emerge from the water came out at once. “All of a sudden, it was like a switch went on,” Carlson said. So you weren’t imagining it.

Is my suffering worse than yours?

My dad used to console me by saying mosquitoes couldn’t resist my “sweet blood.” Carlson says people like me have “won the genetic lottery.” Fact is, some people are more attractive to mosquitoes because of their underlying biology — the amounts of carbon dioxide they emit or the natural scents they carry, for example.

Some of it can be activity-based, Aliota adds. If you’re huffing and puffing on a strenuous hike, you might feel them coming for you. Potential bummer alert for your July 4th gathering: Alcohol consumption can also stimulate mosquito attraction.

They also detect us by body heat. So if your body temperature naturally runs warmer than the average person, consider yourself desirable.

“That’s why if you’re ever around a pregnant woman in the summertime, she tends to get more mosquito bites than anybody else,” Carlson said.

So the solution is clear: Invite a pregnant friend to your barbecue.

What works?

If you’re just sitting in the backyard or are hosting a patio get-together, one of the most effective things you can do is plug in an oscillating fan to keep the air moving, Aliota said. The wind can help keep mosquitoes from finding you and your guests.

And don’t forget the bug spray. “I am a strong believer of using DEET,” said Aliota, though for kids he recommends using a spray with picaridin.

Permethrin is another treatment that can be applied directly to clothing and gear rather than directly to the skin. Before sending my kid to a weeklong camp in the woods, I sprayed his socks, pants, shoes and shirts to keep him a little safer from mosquitoes and ticks.

To provide a spatial repellent to cover an outdoor area such as a deck or patio, both Aliota and Carlson said they were intrigued by Thermacell, which diffuses a synthetic version of a substance found in chrysanthemum flowers. “I’ve seen some evidence that suggests they work pretty well,” Aliota said. “I was actually looking to buy some.”

Should I eat garlic?

“I think you’d have to eat a lot of garlic to have any kind of repellent effect,” Aliota said.

Same goes for those citronella candles — or planting citronella, said Carlson. “Your yard has to be entirely made out of citronella plants for it to have any impact.”

What about mosquito traps?

These gadgets promise to lure mosquitoes by mimicking human breath and then killing them by drowning, electrocution or other means. Some have been studied and shown to be effective, but Carlson recommends staying away from these products because they may invite even more mosquitoes to your area and won’t succeed in killing them all.

He also advises that people use caution when purchasing foggers that can be applied to your yard. These products can knock down mosquitoes for a number of hours, but may kill more than mosquitoes — such as pollinators and other insects beneficial to the environment. Consider hiring a licensed professional who is trained to apply proper dosages by checking the state’s Department of Agriculture lookup page at bit.ly/3ONGLX5.

Choose wardrobe items wisely

Trust me, black leggings will only invite an attack on your posterior. A mosquito is drawn to dark clothing, and stretchy, tight fabric will not prevent its long proboscis from piercing your skin. Best to opt for a lighter color, as well. Remember the three L’s, Carlson advises: “Light, loose and long sleeves.”

Silver linings

Sometimes it’s easy to lose sight of the fact that in other parts of the world, “mosquitoes are Public Health Enemy No. 1,” said Aliota.

Even in Minnesota, cases of West Nile Virus pop up every summer. But our cold winters are good for something, he adds. The species that transmit the pathogens that cause dengue or Zika virus aren’t established in our state.

What’s the 2022 mosquito forecast?

“Predicting what the rest of the summer is going to be like for mosquitoes is essentially like predicting the weather,” Aliota said. “It’s somewhat unreliable, and it can vary depending on the mosquito species.”

Although more than 50 mosquito species are found in Minnesota, the ones that are most likely biting you in your yard are aedes vexans. They lay their eggs in tree holes or other containers that collect water and thrive when there are intermittent thunderstorms. This species is the most likely to peak at this time of year.

On the other hand, a wet spring followed by drought conditions in the summer are favorable for culex mosquitoes, the kind that transmit West Nile. They usually peak a little later in the summer, after many of the aedes vexans mosquitoes have subsided, Carlson said.

So keep taking precautions until around mid-September, when the nights have begun to cool off.

Until then, treat those itchy bites with the most research-based remedy around: Use your thumbnail to mark them with an X.


Leave a Comment