Services
>
Drainage & Sewer
>
Keep Water Safe & Clean
>
West Nile Virus
Mosquito Control in Catch Basins
Seattle Public Utilities (SPU) has a program to control mosquito breeding in its drainage catch basins.
Drainage catch basins are underground structures designed to hold stormwater runoff that drains from the street or other areas. These structures are designed to hold water, they are often an ideal environment for mosquito breeding, because the insects need only a small amount of water to lay eggs.
In order to control mosquito breeding in these structures, licensed applicators apply a very low toxicity larvicide to the catch basin. The larvicide kills mosquito larvae in the water.
|
|
The larvicide used is in solid form and is placed in catch basins six to ten feet underground. Catch basins are secured structures and are inaccessible to the general public.
The treatment is weather-dependent and is scheduled to occur in July and August, unless West Nile virus disease conditions warrant treating at other times.
SPU will use bacillus sphaericus, a naturally-occurring soil bacterium. When used according to label rates, this biological larvicide does not appear to harm mammals, birds, fish, or most non-target invertebrates (insects and worms). The Organic Materials Review Institute recently listed a common bacillus sphaericus-based product for control of mosquitoes in the production of organic food. Health officials support the use of biological larvicides for mosquito control.
SPU Research
During 2005 and 2006, SPU studied mosquito breeding in its catch basins and how well larvicide works to treat them. You may click on the links below to see reports about this research.
Links to other sites
WA Department of Health – Bacillus Sphaericus
Material Safety Data Sheet – Bacillus Sphaericus (PDF)
|
|
