Mosquitoes and Midges

Why do mosquitoes feed on humans?

Only adult female mosquitoes requires a blood meal (protein) to produce eggs. Mosquitoes are attracted to carbon dioxide (exhaled air), warmth, body odour, perspiration and light.

Does the City spray lakes or man-made water bodies and structures?

No. The City's lake systems are of significant environmental importance. The City does not chemically treat any of the natural lakes or wetlands in Cockburn for mosquitoes. Health Services treat mosquito breeding in man-made water bodies with environmentally sensitive treatment options. The City focuses on residential swimming pools that have not been maintained through filtration and chlorination, as they can provide breeding grounds for mosquitoes. The City uses data from the Nearmaps system, which is updated monthly, to identify unmaintained pools.

What can I do to protect myself and my home?

• Reduce outdoor activities during dawn and dusk  
• Cover up by wearing light coloured long sleeve shirts and long pants that are loose fitting
• Apply personal insect repellent containing DEET or Picaridin if possible
• Ensure fly screens to doors and windows are fitted and maintained
• Check your property for potential breeding sources:
  • Empty pot plant bases weekly or fill the base with sand to absorb water
  • Bromeliads and other water holding plants should be washed out weekly
  • Clean roof gutters out regularly and trim back trees which can block gutters
  • Ensure rainwater tank overflow pipes are screened and access covers fitted securely
  • Keep swimming pools maintained
  • Ensure plumbing and vents to septic tanks are screened
  • Wash out birdbaths and ornamental pools weekly.

Midge management

What are midges?

Chironomidae, commonly known as midge, are a large and diverse family of flies. They are commonly known as "non-biting midges." Often confused with mosquitoes, no members of this family are blood-feeders. Adults feed on nectar or similar substances, if they feed at all.
Midge larvae are nearly all aquatic or sub-aquatic, and are a very important part of many freshwater ecosystems.

Why do we monitor midge numbers?

It is important to monitor midge numbers to help predict and minimise the nuisance caused to residents living near wetlands. Nuisance midge problems are often a sign of a more significant problem such as wetland ecosystem degradation. Wetland areas need to be well maintained and preserved to provide wildlife, including invertebrates, with suitable habitats.

Midge management program

The City’s midge monitoring and control program includes:

• Conducting regular monitoring programs of water  and sediment  samples throughout the midge season
• Revegetation programs including the installation  of nutrient stripping basins
• Promotion of waterwise gardens
• Liaising with other management agencies such as  the Water Corporation and the Department of Parks  and Wildlife
• Liaising with experts from tertiary institutions  to further understand and control nuisance midge
• Trialling treatments methods specific to midge
• Implementing a control program in response to  midge larvae numbers and customer complaints
• Installing light traps and developing new and more efficient (environmentally-friendly) methods  for midge control such as the installation of Bat boxes
• Aerial chemical treatment of lakes when warranted
• Maintaining revegetation buffers around wetlands
• Supporting appropriate land use adjacent to wetlands
• Public education
• Continuously reviewing the City’s Integrated Midge Control Strategy.

Long term midge control

Long term options are the most desirable as they address the underlying causes of midge breeding such as nutrient enrichment and the loss of natural vegetation surrounding wetlands. Control measures include:

• The re-establishment of fringing vegetation surrounding wetlands to take up nutrients, shade and cool the water and to screen light from residential areas as midge are attracted to lights
• Preventing nutrients from entering lake systems by reducing fertiliser use around wetlands and encouraging residents to minimise runoff from their own properties
• The introduction of bat boxes to increase bat populations that feed on adult midge.

Improving water quality will lead to conditions which are less favourable to midges, resulting in lower midge numbers in the long term.

Short term midge control

These options only treat the nuisance symptoms and not the underlying cause of excessive midge numbers. Control measures include:

• Use of growth inhibitors specific to midge which prevent larvae from progressing  to the adult stage
• Using light traps for flying adult midges
• Installing bat boxes.

Problems associated with overuse of larvicide and insecticide include the development of resistance and killing of non-target organisms such as natural midge predators.

What can I do to minimise midge problems?

If you are experiencing midge problems, you can take the following actions:

• Keep windows and doors closed
• Install fine mesh insect screens
• Place electrocuting light traps around your property
• Avoid light coloured surfaces around your home - these reflect light and attract midges
• Green and dark blue surfaces are most desirable
• Screen light from the sources of midges
• Reduce the number and wattage of outside lights
• Use yellow external lights or sensor security lights
• Use outdoor foggers (insecticides) when entertaining.

 For more information contact Environmental Services on 08 9411 3444.