Northwest Mosquito Abatement District (NWMAD) seeks to provide the community the best possible mosquito control through the District’s Integrated Mosquito Management Practices.
District Map
Northwest Mosquito Abatement District covers a land area of approximately two hundred forty-two (242) square miles. Each integrated mosquito management practice plays an important part in protecting our constituents from nuisance and disease vector mosquitoes. This map shows all townships and borders of the district. Visit the Search the District page to find interactive maps.
Water Management
NWMAD field technicians aim to empty artificial containers holding water as efforts to reduce the number of sites mosquitoes can lay eggs. Artificial containers can include buckets, bird baths, cans, old tires and more. Disease vector mosquitoes, those carrying West Nile Virus, are most likely to lay eggs in artificial containers holding water. As field technicians cannot reach or find all containers of water in our district, NWMAD encourages the community to empty containers holding water on their property every 5 to 7 days. Learn more about water management around your property on the Fight the Bite page.
Abatement
Northwest Mosquito Abatement District implements two main forms of mosquito abatement.
Daytime larvicide is the abatement of mosquitoes in the larval stage. This is the most effective form of mosquito control. Learn more about larval surveillance and larvicide below.
Adulticide is the abatement of adult mosquitoes. This type of treatment depends on the count of disease-borne mosquitoes in a trap and is used infrequently. Learn more about adult surveillance and adulticide below.
Larval Surveillance & Larvicide
Mosquito eggs can survive long periods of time in dry conditions, with even a tablespoon of water, they can hatch into larvae. That is why it is imperative for Field Technicians to routinely check mapped sites in the district throughout the season. Sites can include roadside ditches, forest preserves, catch basins and more. Even if these look dry from a distance, corners hidden in shade or partially covered can retain enough water for mosquitoes to hatch. Field technicians will use dip sticks (dippers) to check standing water for mosquito larvae. If the sample is positive, the Technician will perform larvicide. Learn more about larval surveillance and larvicide on the daytime larvicide page.
Adult Surveillance
Not all mosquitoes can be sought out and treated for at the larval stage. It is important for NWMAD to track populations of adult mosquitoes in the district as well. Entomologist Dr. Patrick Irwin and his team of lab assistants perform daily, Monday through Friday, checks of adult mosquito traps throughout the district. They bring the adult mosquitoes back to the lab to identify the species and count the amount of each type of mosquito found. This way Dr. Irwin and his team can keep track of the amount of West Nile Virus carrying mosquitoes in the district. Learn more about the process of adult surveillance on the Mosquito Information page.
Adulticide
When Dr. Irwin and his team report adult mosquito populations have exceeded a threshold or multiple mosquitoes with West Nile Virus have been found, NWMAD will perform abatement of adult mosquitoes, also known as adulticiding. Adulticiding is performed after dusk and has strict weather rules from the EPA on when spraying can occur. Areas to be sprayed will always be announced the day of, after 2 pm, on the Night Spray Schedule page. Learn more about spraying for adult mosquitoes on our Adulticide page.