The City of Kwinana and the Department of Health are working collaboratively to manage mosquito numbers at The Spectacles beginning with a trial of aerial treatment at selected sites which is expected to take place in March.
The City has undertaken mosquito trapping at The Spectacles since 2018.
In 2021 the Department of Health confirmed the presence of Ross River Virus (RRV) in Culex annulirostris mosquitoes collected at The Spectacles over three occasions from January to March.
This mosquito species can travel up to 10km and is commonly seen between January and April.
The Spectacles wetland will require control measures due to detection of high concentrations of mosquito larvae in shallow pools under mature paperbark trees.
Aerial application of larvicides has been recommended as the most appropriate control, and its effectiveness will be studied to determine ongoing treatment and a suitable application rate.
The aerial larvicides used in Western Australia are S-methoprene and Bacillus thuringiensis subspecies israelensis (Bti).
These larvicides are target-specific to mosquitoes and have negligible impact on other aquatic and terrestrial species when used at label rates. The products being applied are also non-toxic to humans.
The Department of Health will fully cover the costs of this trial including the helicopter costs and larvicides.
Aerial larviciding is often carried out across the Peel, Leschenault and Geographe regions by Heliwest which is the current contractor for the Department of Health mosquito programs.
If the initial trial proves to be successful, treatment may be carried out in future if ongoing monitoring results indicate a rise in significant mosquito breeding, and if there is adequate financial support to implement the treatment.
The City is also working with the Water Corporation to ensure that the Peel Main Drain that runs through the North and South wetland is cleared from overgrown vegetation.
Based on the availability of the helicopter contractor, environmental and meteorological factors, and larval activity at The Spectacles, it is anticipated this trial will take place during one morning on the first week of March.
The City has access permission and authorisation to undertake the trial from the Department of Biodiversity, Conservation and Attractions as land managers of The Spectacles and Water Corporation as the agency responsible for the management of the Peel Main Drain.
Temporary signage will be erected by the Department of Biodiversity, Conservations and Attractions at entry and exit paths to inform park visitors of aerial mosquito treatments.
Closing full public access is not necessary as the main treatment areas are away from walk trails.
For more information, and the FAQ’s regarding the aerial trial, visit Insect and Pest Management