Mosquito Control Program

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Employee spraying insecticide outdoors

Mosquito Control Program

The Town of Georgina operates a small, localized, nuisance Mosquito Control Program. This outline has been prepared to provide information about the Town's current activities and to provide links to other information sources regarding mosquito control.


The quality of life for residents of Pefferlaw and Udora have been impacted by significant populations of “nuisance” mosquitoes. The catchment basin of the Pefferlaw area is part of the Lake Simcoe watershed system, and is drained by the Pefferlaw River which runs from south to north. Important mosquito development sites are situated within the Pefferlaw River flood plain. The high water table and the flat topography creates a haven for mosquito reproduction and favour the creation of large mosquito development sites, many of which remain flooded throughout the season.

Program Area 

Please consult the PDF icon 2022 Mosquito Control Program Map (4.18 MB)


Mosquitoes establish their larval development sites in environments containing stagnant waters, such as wetlands, marshes, bogs, flood plains, poorly drained forests, ditches, etc. Certain species prefer temporary environments (rainfall dependent) while others prefer permanent sites (existing throughout the seasons). Some species have many generations per season (multivoltine) while others have only one generation (univoltine). In addition, of the approximately 30 species found in the area, some are a nuisance to the residents, some are only targeting specific animal species (amphibian, birds, etc). 

Bacillus thuringiensis israelensis (Bti)

To control mosquitoes, the program uses a biological insecticide called Bacillus thuringiensis israelensis (Bti). This bacteria is unique in that it is toxic only to the larval stages of dipteran insects such as mosquitoes and black flies. It has no impact on other types of insects, amphibians, fish or wildlife. The active ingredient in Bti is a small diamond shaped protein crystal that is produced by the fermentation of the bacterium. This bacterium occurs naturally in the soil and is not the result of genetic manipulation.