Fort Collins to spray for mosquitoes Aug. 14-15 & Aug. 19-20

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In accordance with the City’s West Nile Virus Management Policy, the City of Fort Collins will spray for adult mosquitoes beginning at dusk on Aug. 14-15 and Aug. 19-20. Weather permitting, truck-based fogging will take place:

North of Mulberry Street – Wednesday, Aug. 14 & Monday, Aug. 19
South of Mulberry Street – Thursday, Aug. 15 & Tuesday, Aug. 20

A map of spray zones is attached and available online at

The City’s contractor, Colorado Mosquito Control, will use a permethrin-based product to be applied in a fine mist. Spraying will begin at dusk according to the schedule above, and will continue until 2 a.m. the following morning for each application. To minimize pesticide exposure, residents should stay indoors and keep doors and windows closed for 30 to 60 minutes after spraying occurs. It’s recommended that residents bring pets indoors as well. Residents can further minimize pesticide exposure by covering organic gardens, ponds, and water features with a sheet or tarp.

The decision to spray for mosquitos follows the recommendation by Dr. Adrienne LeBailly, Larimer County Department of Health and Environment Director, and a majority recommendation from the City of Fort Collins West Nile Advisory panel.

The City of Fort Collins’ West Nile Virus Management Policy aims to reduce the risk of human West Nile virus infection while limiting adverse human health and environmental impacts. The Policy prescribes a data-driven approach to determining when spraying for adult mosquitos should occur. In 2008, a Technical Advisory Committee comprised of community members and professional experts with diverse perspectives developed Program Response Guidelines that establish thresholds for action. The Guidelines were updated in 2013. The West Nile Management Policy and Program Response Guidelines are available online at

Any recommendation for spraying originates from the Larimer County Department of Health and Environment (LCDHE) and is preceded by a detailed analysis of West Nile virus risk by a three-person West Nile Advisory panel that provides feedback to the City Manager. Per the adopted West Nile Virus Management Police, the City Manager ultimately authorizes spraying.

Residents who live in the spray areas and who are listed with a phone number and address in the White Pages will receive a phone call on their respective spraying dates notifying them of nearby mosquito spraying activity. The City also offers an automatic notification system that allows residents to receive courtesy notices via email any time spraying for adult mosquitoes is scheduled for their neighborhood. To register for future notices, visit Fort Collins residents without internet access can sign up to receive phone notifications by calling Colorado Mosquito Control at 970-663-5697 or 970-962-2583.

In addition to City-managed adult mosquito spraying, some homeowner’s associations may hire private contractors to conduct additional spraying in their neighborhoods. The City of Fort Collins will not provide courtesy notifications for HOA-managed spray programs.

Residents who are registered with the Colorado Department of Agriculture Pesticide Sensitivity Registry will be contacted by Colorado Mosquito Control to discuss shut-off protocol. There is no other opt-out provision.


  1. I do not want it sprayed or have any on my property, what is the procedure to not have it sprayed?????

  2. We were working in the mountains all week and had no idea of the fiasco taking place in our fair city until arriving home. What are our city council members thinking? I awoke at my usual time 5:30 am Saturday not to hear the birds singing, they are gone, Friday afternoon we found two dead rabbits in our front lawn, and how many others that we cannot see. What about the long term effects. Did these questions enter their mind before giving the thumbs down ?

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