Mosquito management program

Sydney Olympic Park is one of several locations along the Parramatta River that contains saltmarsh meadows and mangrove forests. These valuable ecosystems are natural breeding habitats for saltwater mosquitoes (Aedes vigilax). Saltwater mosquitoes are active during the warmer months, and their population peaks during summer and early autumn, following rainfall and unusually high tides.

Breeding season

Mosquitoes are most active during warmer months. Sydney Olympic Park Authority manages aerial helicopter treatments and ground-based spraying that occurs within the tidal wetlands of Newington Nature Reserve and Badu Mangroves. Spraying is organised to take place just after a high tide event or after heavy rains, when peak hatching occurs.

Treatment dates

The need for and timing of a treatment is based on scientific monitoring of larvae numbers, tides, rainfall and temperature. Potential treatment dates based on tide predictions are subject to change, and treatments may also be conducted on other dates, depending on monitored larval counts, rainfall, temperature and tide. Please check back for upcoming dates.

What are we doing to manage mosquitos

Sydney Olympic Park Authority in collaboration with scientists from NSW Health Pathology implements an ecologically sustainable mosquito management program. This program delivers an annual monitoring and advisory service that guides a mosquito management program aimed to reduce pest mosquitoes on lands under our care to improve comfort levels for people living, visiting and working in the area.

The program involves:

  • Reducing mosquito habitats through improving tidal flushing of degraded wetlands. Over the past 20 years, mosquito populations have reduced as a result in these habitats.
  • Helicopter and ground spraying of an environmentally-friendly mosquito control product containing the bacterium Bacillus thuringiensis israeiliensis (Bti) in mosquito breeding hotspots.


Bti is designed to kill mosquito larvae without harming people, pets or the general environment. It targets the gut wall of larvae, killing them before they become adults. Post-treatment monitoring by Sydney University’s Department of Medical Entomology has shown that larval mosquito populations are generally reduced by 90% or more.

Mosquito breeding times and treatment days are highly dependent on tides, rainfall and temperature. Bti needs to be applied at a specific stage of the mosquito lifecycle to be effective, so treatment windows are very short. Between four to eight treatments are generally applied per season.

Download Material Safety Data Sheet for Bti

Key facts about mosquitos

  • There are 30 different types of mosquitoes found in the Sydney area.
  • Mosquitoes are important for our environment. Mosquitoes provide food for other insects, birds, bats, frogs and fish. Some mosquitos may also help to pollinate plants.
  • Not all mosquitoes are pests. Some bite birds and frogs. One species doesn’t bite at all.
  • Female mosquitoes bite as they need blood to develop their eggs. Mosquitoes also feed on nectar and other plant juices.
  • Mosquitoes have complicated life cycles. They spend the first half of their life in water, the other flying about.
  • The risk to public health by mosquito-borne disease, such as Ross River virus, is considered very low in areas of the Parramatta River estuary. Malaria and Dengue are not present in NSW. The irritation and annoyance caused by the bite of the saltwater mosquito can be significant.
  • Mosquitoes cannot spread the virus that causes COVID-19.


You can help reduce mosquito numbers and impacts by:

  • eliminating mosquito breeding sites around your home and workplace and
  • covering up with loose long-sleeved clothing and using repellent when outdoors, particularly around dawn and dusk when mosquitoes are most active.

Further information

View boundary map of where mosquito aerial spraying will occur.
View SOPA's Mosquito Awareness and Protection flyer to learn more about mosquitoes and the management program.


If you have any enquiries about the Mosquito Management Program, please contact the SOPA via