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West Nile Virus

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FAQs for Mosquito Spraying Due to Risk of West Nile Virus

Where can I find a map, and what do the numbers and colors on the map mean?

Maps of the spraying zones will be posted online when spraying is announced. The numbers and colors are the designated areas that have been identified for spraying. They are meant to help the viewer differentiate between areas quickly.

What chemical will you use?

The name of the product is Aqua-Kontrol 30-30. The active ingredient is Permethrin and it is applied at a rate of .007 lbs. of Permethrin per acre by a truck–mounted ultralow volume spray rig. It is an EPA–approved product for mosquito control. The West Nile Virus Technical Advisory Committee researched many products for this type of control and this is the best product currently on the market for our application. Permethrin degrades in sunlight and in water, so a good practice would be to irrigate gardens the morning after application.

How does permethrin work?

Permethrin can affect insects if they eat it or touch it. Permethrin affects the nervous system in insects. Permethrin is more toxic to insects than it is to people and dogs. This is because insects can't break it down as quickly as people and dogs. Cats are more sensitive to permethrin than dogs or people.

Learn more about permethrin.

What precautions should I take to minimize exposure during mosquito spraying?

To minimize pesticide exposure, residents should stay indoors and keep doors and windows closed for 30-60 minutes after spraying occurs. Bring pets indoors as well.

Is it safe for pets? Can I let them outside?

It is recommended that family pets be brought inside during the spraying application. Please allow at least 30 minutes to pass before going outside or letting your pet outside.

How should I protect water features or ponds in my yard?

To try to reduce the exposure to pesticides, you could take the time to cover any water features in your yard. A tarp or a sheet will suffice; the chemical is applied as a mist and it will not penetrate the sheet.

What about protecting my garden?

You can minimize exposure to the pesticides by covering your garden with a tarp or sheet. The chemical does not penetrate the skin of vegetables, so if your garden was uncovered, washing vegetables with warm soap and water will remove any pesticide residue.

Can I opt out of the spraying?

No. The risk of West Nile virus is considered a public health issue. The City will only make special accommodations for those residents who are listed on the Colorado Department of Agriculture’s Pesticide Sensitive Registry. More information is available on their website.

While the State of Colorado does not guarantee municipalities will make mosquito-spraying accommodations for those on the registry, the City of Fort Collins does abide by this list in its spray operations.

Can I run my air conditioning?

Yes, you can run your air conditioning, but we recommend covering the fresh air intake for your system while spraying occurs.

Why didn't I get a notification?

Notifications are sent to people who have opted in to receive West Nile Virus Spraying Community Alerts through the Larimer Emergency Telephone Authority.

There are two ways to opt in: 

  • Email or Phone Call Alerts: Create an account and under "My Alert Subscriptions" click "Community Alerts" and then check the "Fort Collins | Poudre Fire Authority" box and check "West Nile Virus Spraying" to receive alerts.
  • Text Alerts: To receive a text message alert, simply text FCWNV to 888-777. 

If you have opted in to receive phone call alerts, you still may not receive one if:

  • You're having phone problems
  • You're not home and don't have an answering machine or voicemail service, or it is not turned on
  • You have a "No Solicitor" recording
  • You have a message where the caller has to hit a key - such as "press 1" - to leave a message
  • You have an answering machine or voicemail greeting that is too long