Reducing Mosquito Breeding Sites

Click here for a PDF “print-friendly” version of this fact sheet

Also see the graphical version

Reducing the number of mosquito breeding areas around your home will lower your risk of getting bitten by a mosquito.

Mosquitoes lay their eggs in standing water. The adult Culex pipiens (common house mosquito), which is the breed most commonly associated as a carrier of West Nile Virus, requires only an inch of standing water to lay its eggs. The following is recommended to reduce the number of mosquito breeding sites around your home:

Standing Water

• Remove all discarded tires from your property. Drill holes in the bottom of tires used for swings or other playground equipment so water cannot collect in them.
• Turn over or remove all water-holding containers (tin cans, plastic jugs) lying around your yard.
• Drill holes in the bottom of any unused containers so water won’t collect.
• Turn over plastic wading pools and wheelbarrows when not in use. Place wading pools and similar items on their sides so the bottom does not become a catch basin.
• Eliminate any standing water that collects on your property.

Bird Baths

• Clean the birdbath every two to three days and change the water. Cleaning the bath removes organic matter and changing the water removes any mosquito eggs or larvae.

Eaves And Drains

• Clear leaves and twigs from eaves troughs, storm and roof gutters throughout the summer.
• Check flat roofs frequently and remove any standing water.

Around Your Yard And Lawn

• Immediately throw away raked leaves and other decaying items such as apples or berries that fall from trees. If they are not to be composted, place them in a closed container until disposal.
• Turn over compost piles on a regular basis.
• Fill in any low depression areas in lawns.
• Remove dense brush and weeds where mosquitoes breed and rest.
• Let your neighbours know about potential mosquito breeding grounds on their property.

Ornamental Ponds/Pools

• Locate ponds in an open space and not sheltered from the wind. The wind may cause movement on the surface of the water that will deter female mosquitoes from laying their eggs.
• Concrete, stone or plastic construction of the pond is preferable to soil sides and bottom. Soil provides organic matter which becomes a source of food for mosquito larvae; this makes the pool/pond a more suitable site for breeding. Concrete, stone or plastic places a barrier between the organics in the soil and the water in the pond, thereby lowering the potential food supply.
• Movement of the water surface will discourage females from laying their eggs. An aerator or fountain should be installed to provide constant movement of the water surface.
• Some fish are known to eat mosquito larvae and have been used to keep the number of larvae in a pond at a minimum.
• Ensure ponds are maintained and all grass clippings, leaves, and debris are removed. This debris supplies the food the larvae need to survive.
• Maintain the area surrounding the pool/pond. Long grasses and weeds along the edge of the pool/pond protect the larvae from potential predators and make it easier for the adults to lay eggs.

Swimming Pools

• When properly maintained, swimming pools provide a very poor mosquito breeding site. They are too deep, have a circulation/filter system, are chlorinated and cleaned regularly. If allowed to sit idle, not maintained or operated, they can become a mosquito breeding area.
• If the pool cover is left on for an extended period, water and organic matter can pool on the low spots. This creates a good breeding site for mosquitoes. By removing the cover weekly and allowing the cover to dry, mosquito larvae and pupa are killed.

Keep Mosquitoes Out Of The House

• Make sure that doors and windows have tight-fitting screens. Repair or replace all torn screens.
• If there are no screens, keep doors and windows closed from early evening to early morning.

Acknowledgement:  Halton Region Health Department