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Fort Collins Continues Spraying Across City


Fort Collins and areas in unincorporated Larimer County will once again see trucks spraying insecticide Thursday night in an attempt to kill mosquitoes infected with the West Nile Virus. 

The focus in Fort Collins will be on areas south of Mulberry Street to the city limits and wrap around 2 am Friday morning, weather permitting.

Mike Calhoon is a Fort Collins Parks Supervisor. He says once this round of spraying concludes, another will take place early next week.  

“You need two applications to break the transmission cycle,” said Calhoon. “There are two types of female mosquitoes flying around town right now. One set, that’s the host seeking. Those are the ones that are going out and biting and looking for the blood meals so they can produce their eggs.”

The other set of mosquitoes, Calhoon says, has developed eggs after biting people and is now looking to lay them.

“What happens when we put out the first spray, it actually impacts the host seeking mosquitoes and we knock those out the first day. Then we wait three to five days because that’s what it takes for the mosquitoes to lay their eggs and go back into a host seeking mode.  When they’re back up in the sky, we’ll hit them again and we’ll knock those mosquitoes out.”

Calhoon says once the 2nd spraying takes effect, new mosquitos will need to re-infect themselves with West Nile thus breaking the transmission cycle and forcing the bugs to find and feed on infected birds once again.

A cool start to September will also reduce the entire population and keep additional spraying from being required.

Areas north of Mulberry Street to the city limits will be sprayed again the night of August 19th, and areas south of Mulberry on the 20th.

Larimer County will also be spraying in select unincorporated areas near Fort Collins. Information can be found here

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