Larvicide (daytime)

Larvicide is mosquito abatement at the larval stage. This is Northwest Mosquito Abatement District’s primary form of mosquito control. Using GIS (Geographic Information System) maps, Field Technicians will locate sites which will be checked for standing water and if mosquito larvae is present. Learn more below about larvicide, the types of sites checked and the technology used by the NWMAD team.

Field technician treating a large site of standing water.

Applying product to targeted water sources for prevention of mosquito larvae. These treatments total 90% of our operations during the summer. With 242 square miles and over 10,000 sources to treat, this is a critical aspect of our day to day operations.

Field Supervisor treating catch basin with slow release briquette.

Applying an extended release products to storm sewers to prevent the development of potentially disease transmitting Culex mosquitoes. This treatment is essential to help protect the public from West Nile Virus because catch basins retain water for extended periods of time and if not regularly flushed by re-occurring rain, this water tends to stagnate and produce Culex mosquitoes. Catch basin treatments start when there is an increase of these Culex mosquitoes in our surveillance traps.

Field Technician treating a backyard catch basin

In addition to the storm drains on residential streets, we also apply the extended release products to storm sewers in resident’s backyards to further control the disease-borne mosquito population. The treatment of these backyard sewers helps protect residents from mosquitoes near their property or areas most likely used during summer months. Such as backyard BBQs, parties, parks, pools, etc.

Bucket tipped over to show standing algae water inside.

Buckets filled with water, like shown in the image, can cause problems for mosquito abatement districts as they are harder to find. This can breed a large amount of disease-borne mosquitoes. Please empty any containers holding standing water on your property every 5 days to prevent mosquito breeding.

View overlooking a bog in a forest preserve during the day.

Wooded areas can contain ponds, lakes and other bodies of water. Sites like these are inspected on a regular basis by Field Technicians and are a main breeding ground for floodwater mosquitoes.

Commonly found in residential areas, roadside ditches can breed both disease-borne mosquitoes as well as floodwater mosquitoes. These sources are inspected on a regular basis by Field Technicians.

Modern technology, like the Mesa tablets, aid our efforts to control mosquito populations in our district. Using GIS maps, field operators are able to more accurately locate and treat sources, providing our team reliable data. NWMAD uses this data to identify trends in treatment of sites and target areas with an abundance of mosquitoes.

The dipper is a small white cup on a long stick which is dipped into the site. The sample in the dipper cup is then checked for mosquito larave presence. The white cup allows the Technician to easily see if there are any larvae wriggling around. If present, the Field Technician will treat the site with the appropriate product. If a sample returns negative, it is best practice to check the site in a few areas. If all are negative, the site is not hosting mosquitoes at the time of the check. Sites can be checked multiple times a season.

More Information on Mosquitoes

You are now familiar with how Northwest Mosquito Abatement District treats for mosquito in the larval stage. The next step is to learn about the life cycle of the mosquito. NWMAD provides educational content on mosquitoes on the Mosquito Information page and ways to protect yourself and family members against bites on the Fight the Bite page.