Mosquito Control

Denver’s Mosquito Management Program uses an approach designed to reduce public health concerns, and provide information and education to residents and business to help them keep mosquito populations at a safe level.

We recognize mosquitoes are a nuisance and can be especially active in neighborhoods that are near waterways and natural areas. The program focuses on preventing mosquitoes through these activities:

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You can protect yourself and your neighbors from mosquito bites in two ways – through prevention and elimination of stagnant water where mosquitoes breed:

Prevention Tips

  • Limit activity outdoors at dusk and dawn
  • Wear protective clothing like pants and long sleeves when outdoors
  • Wear mosquito repellant containing lemon eucalyptus oil, DEET, picaridian, or IR3535
  • For more information on insect repellants, visit EPA’s website.   

Eliminate Mosquito Breeding Sites

  • Frequently remove standing water from containers, tires, birdbaths, gutters and buckets around your home
  • Do not overwater your yard, as it can create standing water in gutters and storm sewers
  • Properly maintain fountains and swimming pools to ensure circulation, or drain and cover if not in use

Mosquito-Proof Your Home

  • Install screens on windows and doors
  • Make sure roof gutters are not clogged and holding water
  • Incorporate xeriscape (non-watered landscaping) to further help reduce the number of mosquitoes in your neighborhood
Understanding mosquitoes is the first step in preventing them. We offer a variety of educational materials and information focused on neighborhood-level prevention of mosquitoes. Please contact Doug Kelley at 720-865-5455.
Denver does not spray for or contract for the spraying of adult mosquitoes. Controlling larvae, which are concentrated in discrete areas of standing water is considerably more effective than targeting adults that are more dispersed.  Spraying provides only a short-term solution that will require multiple applications, and does nothing to eliminate larvae present in standing water. Spraying also produces environmental and public health concerns.  Environmental Health will only spray for mosquitoes if there is a serious outbreak of West Nile Virus.

Denver traps and collects adult mosquitoes at five sites across the city to determine if West Nile Virus (WNV) is present in local mosquito populations. The samples are sent for testing to the Colorado Department of Public Health and Environment.

Testing of adult mosquitoes over the past several years documented the occurrence of WNV in Denver’s adult mosquito populations in 2007, 2011, and 2014.Testing of Denver’s adult mosquitoes did not occur in 2012 and 2013.

Data for neighboring counties indicates that WNV was found in adult mosquitoes throughout the region in 2014, particularly rural areas north of Denver along the front range. 

The number of Culex species (those most likely to carry WNV) collected in Denver traps is comparable to, or lower than, what was found in nearby counties (Adams, Arapahoe, Boulder, Jefferson).

What does this mean for you?

While the risk of exposure to WNV is low, you should still protect yourself.  Mosquitoes generally remain active throughout the summer until September or until colder nights set in (e.g. 40’s).  See “Protect Yourself from Mosquito Bites” for more information.

Larvicide Locations Map

Locations that Environmental Health monitors, treats and traps mosquitoes are shown in the map below. The map is regularly updated with information and results from the monitoring and treatment efforts.

Clicking on the icons will provide a description of the site and information on the most recent site visit.

Icons are located where:

  • Populations of larval (juvenile) mosquitoes are monitored;
  • Larvicides (a biological pesticide that targets larval mosquitoes) are applied when needed, and;
  • Adult mosquitoes are trapped (caught) for identification and testing for West Nile Virus.

Note that information related to the most recent site visit may not be representative of current conditions.

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