Mosquito Management


While Murray is fortunate to border a large area of the Peel Harvey Estuary, its salt marshes provide an ideal breeding ground for mosquitoes. This creates significant risk for residents, especially those living in residential areas in close proximity to the estuary.

Besides being a nuisance, mosquitoes found in Murray can transmit:

  • Ross River Virus
  • Barmah Forest Virus

Current Conditions, Treatment Schedule and Results

Current Conditions

This season has been particularly challenging due to the high level of mosquito breeding activity that has occurred.  

The main driver for mosquito breeding in the Peel region is tidal water surges into the Peel-Harvey Estuary. 

Due to the La Nina effect, we have experienced winter type tides that have persisted through summer and into autumn.  

Vast areas of pooled water around the Estuary have increased the size of breeding areas and warm weather has sped up mosquito larvae development into adults.  This has resulted in greater influxes of mosquitoes in residential areas.

The Peel region has experienced its worst mosquito conditions and numbers in 10 years, with the persistent presence of the ‘summer mosquito’ which travels further, bites more often and is more active during the day than other mosquitoes.

Ross River Virus activity has also been more active this year compared to other years.

Treatments and Results

In response to the increased speed and scale of mosquito breeding, the Shire has nearly doubled the frequency and scale of mosquito treatments compared to previous years, with weekly treatments covering over 300 hectares of mosquito breeding areas.


Location   Size of Treatment Area  Date  
Barragup, Furnissdale, Stakehill, Yunderup, Birchmont, Herron Point  390 7 and 9 March 2021
Barragup, Furnissdale, Stakehill, Yunderup   270 28 February 2021 
Barragup, Furnissdale, Stakehill, Yunderup, Herron Point 181 22 February 2021 
Barragup, Furnissdale, Stakehill, Yunderup, Birchmont, Herron Point  388 12 and 13 February 2021 
Barragup, Furnissdale, Stakehill, Yunderup, Birchmont, Herron Point   276 30 January 2021 
Barragup, Furnissdale, Stakehill, Yunderup  387  23 and 24 January 2021 
Barragup, Furnissdale, Stakehill, Yunderup, Birchmont, Herron Point   406 12 and 13 January 2021
Barragup, Furnissdale, Stakehill, Yunderup, Birchmont, Herron Point  335  4 and 5 January 2021


How is the mosquito treatment schedule determined?

Tides that flood saltmarshes lead to mosquito eggs hatching.

Tides in the Peel Harvey Estuary can rise unexpectedly due to low pressure systems, northerly winds and local climatic events.

As a guide when tides in the Peel Region reach 0.76m, hatching of mosquito eggs is likely to be initiated on most breeding sites.

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

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

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

Larviciding is the main method of mosquito reduction in the Peel Region. This technique targets the mosquito larvae before they emerge as adults and is the most effective control method to reduce adult populations. 

As large areas (up to 600hectares of saltmarsh) need to be treated the larvicides must be applied by helicopter.

The two main products used are sand based S - methoprene and a liquid product 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.

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

Whilst the vast majority of larvicide treatments are effective in reducing mosquito populations, the limitations of the larvicides and environmental conditions do not permit total eradication. This is why even after successful treatments there will always be residual mosquito activity.

Larviciding treatments are not always effective due to environmental conditions and it is important that you take personal protective measures.

Protect Yourself

There is no cure or vaccine to protect against mosquito-borne diseases acquired in Australia. The only way to prevent infection is to avoid being bitten.

The worst months for Murray (and the wider South West region) are spring and summer, September to March.

Mosquitoes breed all year round however, so it is important that we stay vigilant.

Protect yourself from being bitten

Cover Up

  •  Wear long, loose-fitting, light coloured clothing, covering as much of the body as you can


  •  When outdoors, apply insect repellent containing DEET (diethyltoluamide) or picaridin evenly to exposed skin


  •  Try and stay indoors during increased mosquito activity, such as at dawn and dusk

Reduce mosquito breeding around your home and property

Clean Up

  • 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

Peel Mosquito Management Group

The largest mosquito management partnership of its type in Western Australia, aimed at reducing human cases of mosquito borne disease and minimising the nuisance caused by mosquitoes. 

Members Include:

  • Department of Health
  • City of Mandurah
  • Shire of Murray
  • City of Rockingham
  • Shire of Waroona
  • With assistance provided by The University of Western Australia

Mosquitoes are a part of life in the Peel Region.Without the programs operation, mosquito borne disease and mosquito populations in our region would be significantly higher.

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