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.
Overview
Large mosquito populations in Pefferlaw have affected residents' quality of life. The area is part of the Lake Simcoe watershed, with the Pefferlaw River running south to north.
Mosquitoes breed in the Pefferlaw River floodplain, where a high-water table and flat land create ideal conditions. Some areas remain flooded all season.
To help manage mosquito populations, the Town of Georgina’s contractor applies a biological larvicide in Pefferlaw, Port Bolster and Udora, covering about 3,908 hectares.
The larvicide, Bacillus thuringiensis israelensis (Bti), targets mosquito larvae after snowmelt. It is applied by helicopter and ground equipment.
Mosquito larvae develop in stagnant water, including wetlands, marshes, bogs, floodplains, forests and ditches. Some species breed multiple times per season, while others have only one generation.
Program history
In 2006 and 2007, a two-year study was done on mosquito populations in the Pefferlaw area of Georgina. The study looked at both mosquito larvae and adults, as well as breeding sites. The goal was to create a program that would improve life for residents and visitors while protecting the environment.
The study found that the main nuisance mosquitoes in Pefferlaw were species from the Ochlerotatus group, such as Ochlerotatus stimulans, Oc. canadensis, Oc. abseratus-punctor, and Oc. provocans. These mosquitoes breed in temporary water created by spring snowmelt or when the Pefferlaw River overflows. Their eggs need a dry period followed by freezing before hatching, which happens when they’re submerged in water and oxygen levels drop. Other mosquitoes, such as Aedes vexans and Coquillettidia perturbans, hatch later in the season and rely on rainfall.
In 2008, and again from 2016 to 2024, GDG Canada started a mosquito control program in Georgina using the biological larvicide Bacillus thuringiensis israelensis (Bti). The program aims to reduce the number of spring mosquitoes without harming local plants and animals.
Program area
View or download the 2025 Mosquito Control Program coverage map
Program contact
Operations Admin (Roads, Forestry and Stormwater)
905-476-4301, ext. 5905
roadsadmin@georgina.ca
Frequently asked questions
What products are used?
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.”
What is B.t.i & is it safe?
Bacillus thuringiensis israelensis (Bti) is a biological insecticide used to control mosquito larvae. It targets only the larvae of certain insects, such as mosquitoes and black flies, without affecting non-target species like amphibians, fish or wildlife. Bti contains a naturally occurring bacterium, which is not genetically modified. The active ingredient is a small protein crystal formed during the bacterium’s fermentation process.
When mosquito larvae feed on water, they ingest the Bti crystals. These crystals become toxic only in the larvae’s gut, where they interact with the gut’s high pH levels, causing the gut walls to break down. This leads to the insect’s death within hours.
Bti is available in two forms: a water-based liquid and a granular product using corn cob granules. The liquid is used for controlling larvae in stagnant water and can also target black flies in running water. The granular formulation floats on standing water, releasing Bti to larvae feeding near the surface.
Bti has been proven to be an effective, cost-efficient solution for mosquito control. It is widely used to reduce mosquito populations that carry diseases like West Nile virus, Encephalitis, Chikungunya, Dengue fever, and Zika virus. In Canada, communities that use Bti in their mosquito control programs help improve residents’ ability to enjoy the outdoors and enhance their quality of life.
How is the product applied?
The product is applied using two application methods. The first application method is ground treatment which is completed by trained field technicians equipped with backpack sprayers. The second application method is aerial which uses a helicopter or drone to treat larger areas or hard to reach sites.
Is the contractor required to obtain any permits prior to spraying?
The contractor is required to obtain approval from the Ministry of Environment, Conservation and Parks (MECP) for ground and aerial application and authorization from Transportation Canada to fly over the treatment area.
How to prevent breeding sites?
To prevent mosquito breeding sites. remove standing water around your home. Mosquitoes like to lay eggs in standing water and its is an ideal breeding ground. It is important to clean standing water from all areas of your property.
- Turn over items that might collect water (buckets, wheelbarrows etc.)
- Keep eaves, gutters and drains clear
- Ensure rain barrels are fitted with a tight screen
- Change bird bath water weekly
How do I opt out of the program
To opt out of the program use one of the following options
- Use the link opt-out link on the webpage
- Call Service Georgina 905-476-4301, ext. 3001 and provide the unique identification code and access code on page 2 of your notices
- Mail in page 2 of the notice to 26557 Civic Centre Rd, Keswick, ON L4P 3G1