Mosquito Management

Ross River Virus has been detected in mosquitos in North Yunderup.

As we head into peak mosquito season, 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.

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.

The mosquito growth cycle is an important consideration because treatments are only effective in the larval stage and not the pupal or adult stage. There may be multiple cohorts of larvae activated by separate trigger 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

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.

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.

Cover Up

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

Repel

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

Avoid

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

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

Secure

• Ensure insect screens are intact