When The City Sprays: Sioux Falls Seeing Increase In Mosquitoes Due To Recent Rain

While much of the state has seen dry conditions, the city of Sioux Falls has a different problem. Due to the recent rain, city officials say the mosquito population has increased.

City of Sioux Falls Environmental Health Program Coordinator Denise Patton said, “This is a mosquito trap that we have throughout the city. It’s called a CO2 baited light trap.”

When the sun sets, 21 mosquito traps set throughout the city are ready.

“There’s a little sensor in the trap that will turn a little light bulb on. It will start to emit CO2 so it mimics our skin and the mosquitoes are drawn to that. They get kind of sucked into a fan that we collect,” said Patton.

The city collects mosquitoes daily. Out of the 43 species in South Dakota, they only worry about a few types.

“We can gauge whether the products for our sprays are working, what species we have and what parts of town because not every every species of mosquito is one we care about. Some don’t bite humans at all,” said Patton.

For example, male mosquitoes don’t bite. While rain tends to bring out mosquitoes that bite a lot, dry conditions bring out those that can carry disease.

Patton said, “If it’s warm and wet, we’re going to see a lot of mosquitoes. They’ll develop through their life cycle quite quickly.”

If a trap catches more than the threshold set for certain mosquitoes a couple nights in a row, the city will spray that zone. If one-third of the zones meet the threshold, the entire city will be treated with a Permethrin-based spray, which is what the city is doing now.

“When we drive by with our truck, there’s a very large cloud that comes out the back that looks kind of ominous, but there’s less than a teaspoon of active ingredient that distributed per acre. The rest is mineral oil,” Patton said.

Two cases of the West Nile Virus have been reported in South Dakota so far this year; in Davison and Lincoln counties.

If you want to know which zone your neighborhood is in, and when the city plans to spray that zone, click here.

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