Mosquitoes

Natural pest control measures are linked with City programs that address habitat loss and recovery, including naturalization programs. Pest Management Lab & Operations works closely with these other programs to ensure habitats are favourable for natural predators, such as bats and dragonflies, to flourish while minimizing undesirable species such as black flies. These programs follow natural processes and may take some time to establish.

Mosquito management programs that use pesticides are still used within the City.
The goal of the program is not to completely eliminate mosquitoes, but to reduce the size of the waves of mosquitoes that emerge after major precipitation events and keep them to a lower, more tolerable level.

Visit Public Notice of Pesticide Programs to see maps detailing where crews plan treatments for mosquitoes, tee insects and weeds.

The City’s mosquito control program has monitored local populations for decades using standard New Jersey light trap data. These traps are commonly used to record changes in the abundance of mosquitoes before and after control campaigns and to compare seasonal and annual fluctuations in population. Additionally, the City is introducing CO2 traps which target mosquitoes by simulating animals exhaling.

The New Jersey light trap data and CO2 trap data are available online. As with any other insect trapping technique, there is an accepted sampling bias. Not all species respond the same to light and CO2 and it's recognized that the species caught in the traps can be in disproportionate numbers to the size of their actual populations. The trap catches are also heavily influenced by ever-changing environmental conditions that affect mosquito flight activity. 

• Report any standing bodies of water that occur within residential areas by contacting 311. These are potential developmental sites for mosquito larvae. City crews will inspect sites and treat if required.
• Drain or fill low-lying areas that collect and retain water that mosquitoes can breed in.
• Items such as old tires, rain barrels or even eavestroughs can be a potential breeding site for some species of mosquitoes. These should be inspected regularly and drained if larvae are found.
• Store pails, buckets and other equipment in such a way that they do not collect rainwater and organic material.
• Keep ornamental pools, ponds and dugouts free of vegetation around the edges.
• Mosquito adults require shelter. Cutting tall grass, weeds and underbrush removes the areas of shade and high humidity that they need for survival.

• You can avoid mosquito bites by staying inside at dawn and dusk when mosquitoes are most active.
• Ensure window and door screens fit tightly and are in good repair to prevent mosquitoes entering the home.
• Keep grass mowed around your property to reduce shady resting sites for adult mosquitoes.
• When outdoors, loose fitting, light coloured clothing will reduce biting. In areas where there are heavy populations of mosquitoes, wear high top boots, long pants of a heavy material and a shirt or jacket of similar material.
• One of the most effective ways to protect yourself from mosquito bites is to wear a mosquito repellent containing DEET. Recommendations for the strength of DEET repellents vary according to age.
  • For adults, concentrations up to 30% DEET are recommended. A limit of 10% DEET is suggested for children 6 months to 12 years of age, but DEET is not recommended for children under 6 months old. Instead, consider protecting babies from mosquito bites using mosquito netting.
• Reduce standing water around your home by cleaning eavestroughs regularly and ensure your yard is free of any items that can hold rainwater. Keep any rain barrels covered with a lid or screen.
• Electronic insect killing traps using ultraviolet or black lights as an attractant are marketed to control pest insects in yards and other outdoor areas. Most evidence indicates that these traps are ineffective in reducing mosquito biting.
• Some manufacturers have attempted to market electronic devices that emit sound waves that supposedly repel mosquitoes. There is little evidence to support these claims. 
• As a last resort, products such as mosquito coils, propane foggers and residual insecticides can offer short-term relief of biting activity around the home.
• For horse owners, a vaccine for horses is available through local veterinarians.
• Educational resources for families about mosquitoes and other local wildlife are available at Just So You Know.

Over 30 different species of mosquitoes representing 6 general groups have been recorded in the Edmonton area. These 6 groups share general similarities in their life cycles including the egg, four larval stages, a pupa and the adult.

In all cases it is only the adult female that feeds on blood, which is used as a source of protein for egg development. Regular energy requirements of both sexes are normally provided by flower nectar.

The predominant mosquitoes in Edmonton belong to the Aedes and Ochlerotatus groups. These mosquitoes typically lay eggs in dry or damp, low-lying areas that are subject to flooding from accumulations of precipitation. Winter is passed in the egg stage and larval hatching requirements distinguish two types: those that hatch in spring and those that hatch later in the summer.

In the spring hatching species, flooded eggs are stimulated to hatch by depletion of the water's oxygen content, caused by a renewal of bacterial action in snowmelt pools. Cool water temperatures promote relatively slow larval development, requiring as long as a month for completion of the aquatic stages.

The resulting adults, of which there is only 1 seasonal generation, normally begin to appear in early to mid-May. Adults of some species last to the end of August, but by mid-July, most have normally died off.

Our major pest species belong to the previously mentioned summer hatching species, characterized by the highly successful Aedes vexans. In this species, flooded eggs hatch when the water temperature exceeds a critical point (about 10°C). Larval development may take as little as 5 days, allowing this species to exploit extremely temporary bodies of water.

Adult females are persistent biters, capable of multiple summer generations and are known to disperse over great distances. Edmonton's heavy summer rainfall, combined with its gently rolling topography of poorly draining, clay-rich soils, creates perfect conditions for the widespread development of huge populations of this particular species.

The other 4 groups of mosquitoes, Anopheles, Coquillettidia, Culex and Culiseta exhibit a variety of life strategies. For the most part, eggs are laid directly on the surface of open water in the form of floating egg rafts. Hatching stimuli are of little significance.

Over-wintering in Anopheles, Culex and Culiseta mainly takes place in the adult stage by fertilized, non blood-fed females. This occurs mostly in animal burrows, rock piles and root cellars. In Coquillettidia, larval stages over-winter restrict development to very permanent water bodies.

Key dates in Edmonton's mosquito control history:

• 2022 - Transition to an entirely ground-based program (aerial program using helicopters discontinued)
• 2020 - First confirmed detection of the northern house mosquito (Culex pipiens), a common West Nile disease vector
• 2020 - Transition from New Jersey Light Traps to BG-Sentinel CO2 traps for mosquito activity monitoring
• 2020 - Fully implemented near real-time automated rain gauge network, replacing manual system
• 2018 - Implemented GPS technology to track and report aerial and roadside applications; began development on GPS system to track granular backpack applications
• 2018 - Transition completely to a biorational pesticide program
• 2018 - Implemented UTVs (utility task vehicles) for off-road treatments
• 2012 - Implemented mobile devices in the field to map standing water and collect larval mosquito development and population data in near real-time
• 2003 - West Nile virus found in Alberta. The province initiated a three-year funding program for mosquito vector detection and source reduction
• 1994 - Implemented a cost-saving efficiency with a one-person ditch crew versus two-person
• 1993 - Discontinued mosquito adulticide program (fogging) targeting the city's river valley and ravine system
• 1993 - Provincial funding assistance eliminated (approximately 50% of budget); eventually all surrounding municipalities discontinued mosquito control in the capital region
• 1993 - Implemented global positioning (GPS) technology to assist helicopter pilots in identifying “no-fly” areas such as noise-sensitive farming operations
• 1991 - Initiated mosquito development site reduction (landfill) program
• 1980 - Introduction of bacterial control product (Bti) for usage in sensitive areas
• 1975 - Edmonton's district-operated mosquito program was centralized under a single pest control unit
• 1973 - Mosquito control monitoring laboratory started
• 1972 - Spraying DDT for mosquitoes was discontinued
• 1953 - Aerial mosquito control initiated