Mosquito Control Program

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.

Mosquito Control Public Notice 2024


The quality of life for residents of Pefferlaw, Port Bolster, 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 create a haven for mosquito reproduction and favour the creation of large mosquito development sites, many of which remain flooded throughout the season.

G.D.G. Canada was contracted by the Town of Georgina to control spring mosquito larvae through the application of a biological larvicide in the communities of Pefferlaw, Port Bolster and Udora. The surface area of the treatment zone is approximately 3908 hectares. The work and treatment are executed by G.D.G. Canada which is a full subsidiary of G.D.G. Environment. 

Between April 1 and May 31, 2024, G.D.G. Canada Ltd. under contract to the Town of Georgina will be conducting a ground and aerial larvicide program to mosquito habitats that impact the residents of the Pefferlaw, Port Bolster and Udora areas. The program will use applications of VectoBac 200G (granular, PCP#18158) or My-Crobe 200G (granular, PCP#34628) and VectoBac 1200L (liquid, PCP#21062) or My-Crobe XT (liquid, PCP#34633).  These products are biological larvicides, with the active ingredient “B.t.i.”    
The biological larvicide (Bacillus thuringiensis israelensis - Bti.) application is targeted to control only the spring mosquito larvae identified following snow melt. The applications of Bti prevent mosquito larvae from completing their development and emerging from the water. These applications are carried out by helicopter or drone and by ground equipment. 

Larval sampling will be conducted in April of 2024 and historical results have revealed the presence of Ochlerotatus stimulans, Ochlerotatus provocans, Ochlerotatus absseratus and Ochlerotatus excrusians (across the territory in April), three aggressive human biters that emerge after snowmelt in non-permanent and permanent standing water sites.

The key to a successful program is monitoring larval development stages and sequencing the treatments based on the larval surveillance data results.

Program area 

View or download the 2024 MCP coverage map

Should you wish to opt out of the 2024 Mosquito Control Program, visit

Program contact

Inquiries related to the delivery of this program can be directed to: 

Danny Hie 
Forestry Supervisor 
905-476-4301, ext. 5905

Contact Us

26557 Civic Centre Rd,
Keswick, ON  L4P 3G1

T: 905-476-4301 / 705-437-2210
F: 905-476-8100

Hours of Operation

Monday to Friday
8:30 a.m. to 4:30 p.m.