Mosquito Management

Peel Mosquito Management Group

Mosquitoes don’t recognise local government boundaries, so we are working cooperatively to achieve effective and sustainable mosquito management.

Members include:

• Department of Health
• City of Mandurah
• Shire of Murray
• City of Rockingham
• Shire of Waroona
• With assistance from University of Western Australia.

This video further explains the collaborative approach of the group and management of mosquitos.

Current Conditions

Ross River Virus is currently active in the region.

Considering recent rainfall, increased tidal activity and rising temperatures, mosquito numbers are likely to remain high with the virus active in the environment.

It is important that residents and visitors take precautions to protect themselves and their loved ones.

Treatments and Results

How is the mosquito treatment schedule determined?

We time our treatments so they have the greatest impact on the mosquito numbers.

Our mosquito control officer monitors breeding sites to assess the extent and location of mosquito breeding and determine when to conduct treatments.

As a guide, when tides reach 0.76m, mosquito eggs in the saltmarshes (key breeding areas) are likely to hatch. Tides in the Peel Harvey Estuary can rise unexpectedly due to low pressure systems, northerly winds and local climatic events.

The mosquito growth cycle is an important consideration because treatments are only effective in the larval stage. There may be multiple groups of larvae activated by separate tides and an ideal application would treat these before any mosquitoes emerge as adults.

Weather conditions are also taken into account because:

• Wind affects helicopter safety and the even distribution of larvicide.
• Rain reduces visibility and clumps granular treatments, affecting its application
• Strong incoming tides can dilute larvicide and strong outgoing tides can wash larvicide out to sea.

How do you treat mosquito breeding areas and is it safe?

Larviciding is the main method of mosquito reduction in the Peel Region. This targets mosquito larvae before they emerge as adults.

Larvicides are applied by helicopter as the treated areas are large – up to 600 hectares of saltmarsh. The two main products used are sand-based S-methoprene and a liquid called Bti (Bacillus thuringiensis israelensis).

These are the most environmentally-appropriate products available and pose very low toxicity to non-target organisms and public health.

This video further explains the treatment process.

A treatment has just been completed. Why are there still mosquitoes?

The vast majority of larvicide treatments are effective in reducing mosquito populations, but even after successful treatments, there will always be residual mosquito activity.

Larviciding treatments are not always 100 per cent effective, due to the limitations of larvicides and environmental conditions, so it’s important that you take also personal protective measures.

This video further explains the environmental conditions impacting treatments.

How can I reduce mosquitoes at my home?

• Remove, empty or cover water-holding containers.
• For horse troughs, poultry drinking vessels of other receptacles, frequently change the water and ensure it remains free from vegetable matter and slime.
• Ensure insect screens are intact.

How can I fight the bite?