What will the mosquito population look like this year? According to Dr. Dan Markowski, technical advisor of the American Mosquito Control Association, that’s the million-dollar question. He’s sharing tips for predicting mosquito populations, reducing mosquito activity with strategic landscaping and protecting yourself from those pesky bites.
Predicting mosquito populations
The mosquito season is long, and it varies by region. But when it comes to creating an environment that’s conducive to mosquitoes, moisture and temperature are consistently the two most important factors.
“The more rainfall, and the warmer it is, generally the more mosquitoes you’ll have,” Markowski says.
He recommends staying tuned to local weather reports throughout the year, because hot weather and heavy rain cause a boost in mosquito populations. For those trying to plan ahead, however, winter snow totals and widespread climate patterns can offer some clues.
While winter rainfall — like the recent atmospheric river in California — will likely dissipate before impacting mosquito populations, peak snowpack levels recorded in the spring can be a good predictor of mosquito populations at the start of the season. In the Western regions of the U.S., snowpack levels of 100% or more lead to a soggy spring as the buildup melts.
As a result, those areas see a more robust batch of early mosquitoes. Based on current snowpack totals, Markowski anticipates seeing average or higher levels of mosquito activity in the West. The early counts may be comparable to last year.
“Last year, California had a banner mosquito season,” Markowski says. “They had a lot of snowpack in the Sierra Nevada mountains, and then an atmospheric river in June. It flooded everything, right in the middle of mosquito season.”
In addition to weather events like an atmospheric river, climate patterns like El Niño and La Niña can affect mosquito populations throughout the season, too. In 2024, it looks like we’ll have to contend with them both.
“We’re in an El Niño that’s creating havoc when it comes to weather right now,” Markowski says. “We’re expecting to go into a La Nina period next, which means a heavy hurricane season.”
In 2020, the last La Niña brought an almost record-setting hurricane season, Markowski adds. And the aftermath of those storms created perfect late summer mosquito breeding conditions.
For those who want to keep tabs on mosquito populations as the season unfolds, Markowski suggests looking for updates with your state or county health department. They often track and publish information about the current abundance and if those pests have been found to be carrying any viruses.
Landscape to prevent mosquitoes
You might not be able to control the weather, but you can suggest landscaping updates that will make your client’s outdoor spaces less hospitable to mosquitoes.
According to Markowski, regular maintenance is a great place to start. Keep lawns mowed and avoid planting tall grasses that create shady environments for mosquitoes to rest in during the day. If a client can’t part with their taller vegetation, suggest that they keep it away from seating and entertainment areas.
Drainage is another thing to keep in mind.
“Don’t allow water to collect on your properties,” he said. “Grade it to avoid ponding or pooling and smooth out any shallow ditches or swales.”
If not installed by the book, French drains can also become a breeding ground for mosquitoes. Take running a corrugated pipe to route water away from a foundation as an example: As water pools in each ridge, that pipe becomes an ideal habitat for Asian Tiger mosquitoes. And water pooling underground can result in a mosquito infestation above.“They can breed in the pipe and fly out,” Markowski says. “You’re creating an amazing mosquito habitat that you can’t even see.”
When dealing with drainage, always install a true French drain, complete with a rock layer to prevent pooling.
While effectiveness is not proven, there are also a number of plants that may repel mosquitoes. It doesn’t hurt that they’re often visually appealing as well. Markowski suggests plants like lavender, mint, rosemary and marigolds to help keep backyard pests at bay.
Protecting yourself
When you’re working outside, you’re bound to encounter at least a mosquito or two. That’s why it’s important for landscaping professionals to protect themselves.
“The two most important things you can do? Wear pants and long-sleeve shirts,” Markowski says. “It’s harder to get bit when you don’t have exposed skin.”He also recommends wearing a good repellent. While a green repellent with natural ingredients like citronella or rosemary might seem like a good option, if you’re an individual that’s typically attractive to mosquitoes, it might not be enough.
When choosing a repellent, don’t bother looking at the brand. Go straight to the ingredient list.
“It’s the active ingredients doing the work,” Markowski says. He recommends proven ingredients like picaridin, oil of lemon eucalyptus, IR3535 and of course, deet.
If you are particularly susceptible to mosquito bites, look for deet. When you start your hunt for your new go-to repellent, get with a small bottle with the lowest active percentage of deet. If that works for you, great. If not, get another small bottle with a higher percentage of deet.
“A lot of people can get by with 5% or 10%. If you get above 30% deet, you start to see the potential for skin reactions,” Markowski says. “Use the least amount that you can get by with. If you do that, you’re generally going to be in really good shape.”
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