Mosquito Control & Information

drawing of the life cycle of a mosquito

Municipal Responsibility

  • To abate existing mosquito breeding sources.
  • To prevent new breeding sites so you can fully use and enjoy your backyard and other municipal recreational facilities.
  • To protect public health and comfort.

Breeding sources we control are created by standing water, which may be found in street catch-basins, subdivision drains, roadside ditches, flood channels, ravines and other public rights-of-way. Routine larviciding, done as necessary throughout the season, will keep these areas mosquito-free. It is our responsibility to work with whatever local, state, or federal agencies may be involved to keep these areas abated.

Property Owner Responsibility

  • To clear your property of any potential breeding sites
  • To prevent any problem areas from reoccurring

Mosquitoes are an all too familiar summer nuisance. They are not only annoying, but they can be transmitters of West Nile Virus, St. Louis encephalitis, malaria and yellow fever to humans, and heartworm to pets.

What is West Nile Virus?

West Nile Virus (WNV) is a mosquito-borne virus that can result in serious illness, and sometimes death. The virus can infect humans, birds, mosquitoes, horses, and other mammals.

Disease Transmission

West Nile Virus is transmitted through the bite of a mosquito. Mosquitoes become infected with the virus by biting a wild bird that has the virus. Though birds are the primary host of West Nile Virus, it is not transmitted directly from birds to people.

Who is at risk of contracting West Nile Virus?

The chance of contracting WNV is higher in persons over 50 years of age, however, any individual living in areas where WNV has been detected is at risk.

Standing water means you could be raising mosquitoes!
Adult flying mosquitoes often rest in tall grass and shrubbery, but they cannot develop there. All mosquitoes need water to complete their life cycle. Some mosquitoes lay their eggs in standing water where they hatch in just a day or two. Other mosquitoes may lay their eggs in old tires, tin cans, or other water-holding containers. The eggs may remain unhatched for weeks or even months until they are covered with water! So after any significant rainfall, remember to remove any standing water from your yard and help keep mosquitoes from hatching.

Yard and Home Checklist

  • Get rid of old tires, tin cans, buckets, drums, bottles or any water-holding containers.              
  • Fill in or drain any low places (puddles, ruts) in yard.
  • Keep drains, ditches and culverts clean of weeds and trash so water will drain properly. 
  • Cover trash containers to keep out rainwater.
  • Repair leaky pipes and outside faucets.
  • Empty plastic wading pool at least once a week and store it indoors when not in use.
  • Make sure your backyard pool is properly cared for while on vacation.
  • Fill in tree rot holes and hollow stumps that hold water with sand or concrete.
  • Change the water in birdbaths and plant pots or drip trays at least once each week.
  • Keep grass cut short and shrubbery well-trimmed around the house so adult mosquitoes will not hide there.

Together, we can control mosquitoes and enjoy the great outdoors.

Mosquito Control Plan


Larviciding will start in late May or early June depending on the weather. Target areas will be identified and appropriate larvicides will be used. Most larvicides will have a 30-day residual. The dates will be recorded for these areas. This procedure will continue all summer with concentrated efforts after a rain of 1" or more.


Three New Jersey light traps and one CO2 trap will be set out in different areas of the city in early June. Counts will start at this time and each trap will be emptied every morning. Only female mosquitoes will be counted. The numbers in each trap will be averaged to see if threshold numbers have been reached (approximately 100 mosquitoes per trap).

Adulticiding (Mosquito Spraying/Fogging)

If threshold levels have been found in our traps, fogging operations will begin. We will usually start fogging some time after 8:00 p.m. if weather conditions are right. The wind needs to be less than 10 M.P.H. and the temperature 58 degrees or above. Two ULV foggers will be used with one on each side of the river. Fogging time will be approximately 4 hours for alleys only. If the trap counts are high, we may fog the avenues along with the alleys. This will take around 5 hours to cover the entire corporate city limits using two machines.

West Nile and other Mosquito-Borne Diseases

City Staff will identify the Culex Tarsalis mosquito, the primary vector of West Nile in Minnesota.  If the average number of Culex Tarsalis mosquitoes in our traps is greater than 10, the City will conduct a city-wide fogging at the next window of opportunity, weather and temperature permitting.