Here’s a look at various methods abatement districts use to control mosquito populations:
Prevention: Districts work to improve drainage to reduce standing water, which can facilitate mosquito breeding. Briquettes that slowly release chemicals also are dropped in catch basins.
Testing: Workers analyze the volume and species of mosquitoes. Some mosquitoes are frozen and tested in a lab for West Nile virus and other diseases.
Larvae: Workers collect water samples in search of mosquito larvae. Various chemical treatments can kill larvae, including a larvicide that prevents them from growing into adults. Districts also use gas-powered sprayers to spread granular bacteria that destroy a larvae’s digestive system.
Adult mosquitoes: When testing shows a high frequency of culex mosquitoes, the breed known to carry West Nile, or when the virus is detected in mosquitoes, birds or humans, districts use trucks to spray pesticides for adult mosquitoes. The mist hangs in the air for about 45 minutes and generally kills about 50 percent of mosquitoes in the area.
