Midges swarm when the spring brings ample food and warm temperatures for breeding. There are no chemicals that can effectively control midge populations, but there are a few measures that can be taken to prevent swarming around your home.

What are midges, and why do they swarm?

Non-biting midges belong to the insect family Chironomidae and inhabit the southwest region of Western Australia. Their larva feed mostly on algae.

During winter and spring, high rainfall washes nutrients into stormwater drains that empty into wetland areas. Blue and blue-green algae feed on these highly concentrated nutrients, and increase in numbers rapidly. After a short time, the algae die and sink to the bottom, providing food for midge larvae.

This sudden increase in their food supply, and the warm temperatures of spring, can result in the life cycle of midges shortening to just 3 weeks. This means there are more adults maturing faster, resulting in a population explosion and swarming.

The population only reduces in summer when the food supply is depleted.

Why can't the City of Stirling spray the midges?

There is no registered chemical for the use against midges, and their preference to breed in deep water (sometimes up to 1.5 m deep) means that any alternative would be ineffective.

What can I do?

There are a number of things you can do to reduce the number of midges around your property:

  • Reduce the wattage and the number of lights on the outside of your house, as lights attract midges.
  • Avoid painting your house light colours, as this reflects light and attracts midges.
  • When entertaining, use outdoor foggers, but follow the instructions provided.
  • Keep windows and doors closed.
  • Place electrocuting light traps around your house.

Contact us

For further information please contact City's Environmental Officer Natural Areas via email or on (08) 9205 8555.