Mosquito Control

Mayflies, a.k.a. lake flies are aquatic insects that are prevalent at Lake Milavec in the spring and typically in May. Although they are annoying, they are an essential food source for fish. Here’s the good news. These flying insects look like mosquitos but they do not bite or sting. Mayflies are often seen as a sign of healthy water ecosystems because they are susceptible to pollutants. We have six tips below on how you can help control mosquitos this summer.

The Town of Frederick Public Works Department is handling mosquito control activities. The Town utilizes a combination of Larvicide activities and Adulticide activities to try and mitigate the occurrence of West Nile Virus. 

Public Works goes out and tries to identify possible breeding grounds and areas where mosquito larvae may thrive. These are typically areas with standing water. Staff then applies larvicides in the form of pellets to control the mosquitoes before they become adults. 

Adulticide spraying occurs on an as-needed basis based upon West Nile conditions (as shown on the County threat level), citizen complaints, and general need. Beginning the week of Tuesday, June 1, town staff will spray on Tuesday and Thursday night 7 p.m. - 10:30 p.m. Spraying cannot occur if the wind is 10MPH or over, or if there is inclement weather. Staff will make a judgment call on whether spraying can occur. Tuesdays and Thursdays are scheduled days for fogging. If more fogging is required Wednesdays and Fridays will be added. The entire Town will be completed every scheduled day.

The Public can do their part in the battle against mosquitos by eliminating sources of standing Water such as disposing of old tires, any type of containers that collect and hold water, Maintaining gutters, etc.  Pet dish and bird bath water should be changed every 2 days.

If you have any questions or concerns feel free to call 720.382.5800. 

Chemicals Used:


  • VectoBac BTI Based. Granular
  • VectoLex BTI Based. Granular
  • Sustain MBG. BTI Based. Granular
  • Altoside BTi Based. Tablets


AquaLeur 20-20. Water Based Permithricide

The materials used in fighting mosquitoes are not hazardous to humans or animals. If you have questions or concerns about the materials used please either email or call Public Works at 720.382.5800. 

Please call the Frederick Public Works at 720.382.5800 if you have mosquito concerns in your area. 

Help Fight Mosquitoes!

You can help fight mosquitoes by doing the following things: 

  • Drain or empty standing water on property/items that hold stagnant water like old tires, poorly maintained gutters, etc. Pet dishes and birdbath water should be changed every two days.
  • Check and eliminate places that accumulate water after irrigating your yard
  • Repair leaky pipes and outside faucets
  • Use insect repellent that contains DEET, Picaridin, oil of lemon eucalyptus, or IR3535
  • Dress in long sleeves and pants that are light in color and loose-fitting when outdoors
  • Avoid being outdoors at dusk and dawn when mosquitos are most activemosquito