Using Chemicals to Control Mosquitoes
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Photo: Department of Medical Entomology, ICPMR |
Mosquitoes can pose a significant health risk by spreading diseases to humans. In Victoria, these diseases include Murray Valley Encephalitis, Ross River Virus and Barmah Forest Virus.
Mosquitoes also cause nuisance and have a major impact on community well being and enjoyment.
Occurring naturally throughout Victoria, mosquitoes are found in highest numbers near still water, such as drains and wetlands, which allow the larvae to develop in large numbers.
Physical barriers such as loose clothing or repellents can reduce the impact of mosquitoes, however, when mosquito populations are high, control measures are required.
Removing breeding habitat for mosquitoes through better drainage or vegetation control are control methods used by government authorities. However it cannot be the sole control measure as there are areas where this is not possible, particularly in environmentally significant wetlands.
Chemical control is, therefore, a necessary component of a mosquito management strategy.
Chemicals for mosquito treatment
Chemicals are generally only used for treating mosquito larvae when it is easier to treat larger numbers of mosquitoes and the impact on off-target species is reduced. In emergency situations, chemicals may be used on adult mosquitoes to restrict the spread of disease.
Chemicals used for mosquito control programs are registered and approved through the Australian Pesticides and Veterinary Medicines Authority (APVMA).
This means all registered products must be effective in controlling mosquitoes, will not jeopardise Australia's trade with other nations and are proven to be safe to people and the environment when used in accordance with the label directions.
There are three main types of insecticides registered specifically for controlling mosquito larvae in Victoria.
These are:
- Organophosphates including temephos, chlorpyrifos, maldison, diazinon, fenthion and pirimiphos-methyl
- Growth inhibitors such as (S)-methoprene
- Biological controls such as Bacillus thuringiensis ssp. Israelensis (BTI)
There is also a wide range of other insecticides registered for controlling adult mosquitoes in Victoria. These include a number of organophosphates and pyrethroids.
The products come in a variety of formulations including granules, liquids, briquettes or sand mixes and there are a wide range of application methods that have been approved by the APVMA. The application methods vary depending on the product but include:
- Direct application to water
- Backpack or hand-reel sprayers
- Boom spraying from vehicles, boats or aircraft
- Fogging with either heated or cold aerosol equipment, back-mounted or vehicle driven.
Issues to consider and recommended chemicals
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There are a wide range of issues which must be considered when undertaking a mosquito control program.
- Is the chemical approved for the specific situation where treatment is required (for example, wetlands and dams)?
- The type, location and size of mosquito populations?
- Breeding sites
- Are non-chemical control options suitable?
- What sensitive areas are nearby the area to be treated with chemical control options?
- Are there crops which may be impacted by damage or residues in produce?
- Are there areas of native flora and fauna which may be affected?
- Is there any risk of unacceptable exposure to residents or users of recreational areas?
Professional advice should be sought prior to undertaking a mosquito control program. Sources of this advice may be licensed pest controllers, local government, Department of Heath, chemical manufacturers or chemical suppliers.
As the type of equipment used to apply these chemicals will often differ from what is normally used by the agricultural industry, it is recommended that licensed pest controllers be used as required.
Specific chemical information
Before using any chemical, read the label and comply with label requirements. Make sure the correct application rate is used and any 'DO NOT' or livestock protection statements are observed. The label will also provide the requirements for health and safety considerations, including the use of Personal Protective Equipment (PPE) for chemical applicators, which must be strictly observed.
Always read the label
Department of Primary Industries (DPI) recommends all people who plan to use chemicals should complete a course in safe use of agvet chemicals. For 'restricted use' chemicals, completion of a course in safe chemical use is a mandatory pre-requisite to the granting of an Agricultural Chemical User Permit (ACUP).
More information
For further information about mosquitoes in general, refer to the 'Framework for Mosquito Management in Victoria' prepared in 2004 by the Department of Sustainability and Environment. It is available on the Department of Health website www.health.vic.gov.au or by calling the Communicable Disease Prevention and Control Unit on 1300 651 160.
If you would like to receive this information/publication in an accessible format (such as large print or audio) please call the Customer Service Centre on 136 186, TTY 1800 122 969, or email customer.service@dpi.vic.gov.au.
