The abnormally wet summer has caused a boom in the mosquito population in
Vermillion, and the city continues to spray for the pesky insect on a consistent basis.
"Most cities run the same; when the mosquito counts are up, we go out and hit them," said Vermillion's Park and Recreation Director David Nelson. "It takes two or three nights to spray the town. We sprayed last week, and we will continue to monitor the (mosquito) population this week."
Vermillion is split into four different spraying zones, and each zone has its own mosquito trap.
The city crews keep an eye on each trap, and when the trap reach a count of 400 mosquitos, the city uses an insecticide fog to help knock the population numbers.
Nelson said the city doesn't spray more because even though the fog presents little risk to people or animals, he doesn't want to subject people to the insecticide. That's why city crews usually wait until 9:30 p.m. – when most folks are inside – to begin spraying.
The city started its efforts to control the mosquito population back in May. The first thing the crew do is apply larvicidal granules to ditches, wetlands and ponds within Vermillion. The granules destroy the larvae before they have a chance to become full-grown mosquitos.
Even though the granules are applied within the city, Nelson said most of the mosquito problem takes place outside the city limits.
"The county doesn't take care of the larvae or spray because there is just too much ground for them to cover," he said. "Depending on the mosquito, they can fly from one to three miles."
The lack of mosquito control in the county combined with the wet and humid weather has caused some big influxes of hatches.
"Four weeks ago, there must have been a huge hatch," Nelson said. "We started fogging to knock it down, and it's gotten better."
One species of mosquito the city crews look out for the most are Culex tarsalis. They are the type of insect that can carry the West Nile virus.
The spraying standards are a bit different for the Culex tarsalis mosquitos. If there are 70 to 75 of them in a trap, then the city will fog to help prevent the spread of the West Nile virus.
Also, any confirmed cases of the West Nile virus will cause the city to spray.
Even during the regular fogging, Nelson said the spray the city uses kills any type of mosquito, even the Culex tarsalis.
So far, there has only been one confirmed case of West Nile in South Dakota this summer, and it was in Brown County in northern part of the state. However, Nelson said the city and the residents should still take protective measures to prevent contracting the disease.
"The virus is suppose to start dying out, but August and September are the two worst months," he said. "Everyone has to help out and eliminate water on boat tarps, bird baths or anything else that holds standing water."
The city also amps up its spraying procedures when there is a big event in town, such as the Fourth of July, or most recently, the South Dakota Pro-Am golf tournament this past weekend.
"Whenever there is a special event, the night or morning before we go out and spray," Nelson said. "The Thursday before the Pro-Am I went out and sprayed the Bluffs (Golf Course)."
Nelson added residents can buy pesticides for mosquitos at the local hardware stores. He said even though the city sprays, sometimes the fog isn't able to get into the backyard's of some houses because of how tall they are.
"It's just like spraying for weeds and you can get it in town," Nelson said. "It takes about 10 minutes, and you have to wear jeans and such, and keep the kids and any animals out of the backyard and for a while after you spray."