The cities of Joondalup and Wanneroo and the Department of Parks and Wildlife have taken the action after monitoring highlighted an increase in populations of the pest.
Residents also have noticed a recent rise in adult midge numbers and swarms on the eastern side of the lakes, likely because of heavy rainfall and high nutrient levels in the water.
The aim is to break the breeding cycle ahead of warmer weather and eliminate a future midge nuisance.
Joondalup Mayor Troy Pickard said chemical treatment of wetlands should be avoided but the treatment was planned because of the high numbers of midge larvae and the prevalence of adult midge.
‘Lake Joondalup and Lake Goollelal are important wetlands and ecosystems, and every endeavour will be made to protect the animal life supported within them,’ he said. ‘The nuisance problem of midges is a symptom of a disturbed ecosystem.
‘Nutrient enrichment is a catchment-wide issue, resulting from the use of fertilisers on gardens, sports grounds and agricultural properties, as well as stormwater run-off.’
Midge larvae will be sampled after the treatment to determine the kill rate and confirm the need for a second treatment two weeks later. The date of treatment will depend on helicopter availability and weather conditions.
The cities of Joondalup and Wanneroo have a register of people who may be hypersensitive to chemical treatment.
Residents wanting to be added to the list should call 9400 4933 for more information.
– Did you know the species of midge that breed in Goollelal and Joondalup lakes do not bite or cause any adverse health effects? But when in big numbers, they can become a nuisance to any nearby residents.