One of the measures to control WNV is to reduce mosquito populations through a process called larviciding. Larviciding involves using pesticides (larvicides) to control mosquitoes when they are in the larval stage of development. This stage occurs in water, after the mosquito eggs hatch, but before the mosquito becomes an adult that bites.
Larvicide is only used in areas where surveillance shows that mosquito larvae are present. Larvicide is only applied when other measures for the reduction and control of breeding sites do not work to minimize the risk of WNV.
Larvicides are chemical and biological products registered for use in Canada by the Pest Management Regulatory Agency (PMRA), a branch of Health Canada.