Our mosquito reduction contractor begins monitoring weather, snowpack and river levels in early-March of each year. These meteorological data help the control staff to determine which larval development sites may be active with mosquito larvae.

Larval Development

There are over 450 known larval development sites in the TNRD. They are classified as “snowmelt” (early-spring ponds and marshes in grasslands and the Logan Lake area that become active very early in the spring), or as “floodwater” (sites along the North and South Thompson Rivers that active with rising water in the spring). 

Mosquito reduction staff search standing water for mosquito larvae before every larvicide treatment and never treat unless larvae are present. This is called mosquito larval monitoring and it is done with a 300-milliliter “dipper.” All larvae are counted, and the “dip counts” are recorded, to align with Ministry of Environment regulations.

Mosquito Trapping Stations

Surveillance staff maintain eight adult mosquito trapping stations within the TNRD. These stations are visited weekly to collect any mosquitoes captured. The samples are taken to a lab, where they are examined under a microscope to determine their species.

Did you know? There are approximately 30 species of mosquitoes in the TNRD

Some species of mosquitoes are persistent and ferocious biters of humans. Some have the potential to transmit disease and others do not bite humans at all.

The species and their abundances are recorded and this information is used by mosquito reduction staff to determine areas of high priority. It is also useful as a means of helping staff find mosquito larvae, since different species develop in different types of larval development habitats. For example, some mosquito species like floodwaters, others develop in permanent or semi-permanent marshes, and others prefer artificial containers.

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