Controlling Mosquitoes


Field surveillance is perhaps the most important component of our program.  Control measures are not undertaken until we have confirmed that a problem exists.  The goal of surveillance is to identify probable breeding habitats, measure production levels and treat areas that contribute to the problem.


Beginning each spring FCMC routinely checks over 1050 mapped sites in Flathead County for the presence of mosquito larva.

A large number of our surveillance visits are initiated as a result of complaint calls by the public.  If you have water on or near your property and you believe this to be a source of mosquito production, email with a description (street name or Township, Range and Section), a contact number and a good time to return your call.

Surveillance and treatment progress can be viewed online at the County GIS site. Read Terms of Use box and click “I Agree”.  Go to Table of Contents box and click the “+” next too Environmental.  Now click the “+”and check the box next to Mosquito Sites.  Zoom into your area to monitor activities.

Points (dots), lines and polygon shapes are color coded too represent their current status
GREEN shapes are not of current concern, have been recently treated or checked by field personnel.

BLUE shapes are on schedule to be checked for the presence of mosquito larva.

RED shapes represent areas that have been identified as producing larva and need to be treated

Source Reduction

Years ago mosquito control districts engaged in huge projects to drain and fill areas known to produce mosquitoes. These efforts, many right in the Kalispell and Evergreen areas, made summer evenings and weekend outings more tolerable by destroying breeding habitats.  Today, many micro environments for mosquito breeding are created unintentionally by simply not keeping water dumped out of containers. Wheel barrows, uncovered boats, tiresand buckets are just a few examples of places mosquitoes can breed.  Anything that can hold water, can become amosquito breeder.

Source reduction is still a part of our program.  Please do your part by:  refilling bird baths with fresh water weekly, recycle unused tires at the Flathead County Landfill, replace water in swimming or wading pools often.  Ornamental ponds with good aeration pumps generally do not produce mosquitoes.

Disease Surveillance

In Montana, West Nile Virus (WNV) is most active during the summer months of June, July, August and into September.  During this period of  time FCMC maintains numerous adult mosquito traps in the Flathead Valley.  Dry ice is used as an attractant to lure adult mosquitoes into containers.  Traps are collected nightly and the mosquitoes are separated by sex and species to be tested for the presence of WNV.


In the event West Nile Virus is detected in Flathead County, this information will become available through Press Releases to the media and on our website.

Montana currently has two species of mosquitoes (Cx. tarsalis  and Cx. pipiens) that are capable of transmitting WNV. The distribution and habitats of these two vectors is generally understood.  Cx. tarsalis is considered a permanent, semi-permanent water mosquito, meaning adult females lay eggs, in egg rafts, on the surface of the water.  Cx. pipiens  also prefer much the same kind of water with a higher amount of organic material.

Mosquito Control

1035 1st Ave West
Kalispell, MT 59901 – 2nd Floor

406-751-8145 main line
406-751-8131 fax