Mosquito control program
Current program
The City of Ballwin contracts with St. Louis County Vector Control Services for mosquito larvae control. The program uses surveillance through trap sites distributed across the county where mosquitoes are collected, counted, and identified by species to guide targeted reduction efforts.
Program changes
In August 2025, the Board of Aldermen unanimously discontinued the previous adulticide (fogging) service. The Board noted that adulticide spraying was not effective in reducing the mosquito population and caused harm to beneficial insects, including pollinators. Concerns included the requirement for direct contact with mosquitoes, weather-dependent dispersal, and limited coverage due to resident opt-outs.
What you can do
Once a week, empty and scrub, turn over, cover, or throw out any items that hold water, including flowerpots, buckets, tires, birdbaths, and pet bowls. Remove standing water from gutters, leaf piles, and vegetation. Tightly cover water storage containers and use wire mesh barriers on rain barrels. Fill tree holes and repair gaps in septic tanks.
Private property treatment
Residents may consult the National Pesticide Information Center at npic.orst.edu for guidance on larvicides and adulticides approved for private property use.
Last reviewed: March 2026