Midges are often called sandflies. Not every sandfly is a midge. Sandfly is a common name for a number of types of small biting insects.
Until recently, midges have been a minor nuisance in Brisbane. However, their presence and nuisance has been increasing. This has been since the arrival of a more serious pest species C. ornatus in the western suburbs.
Effect of midges
Midge bites can:
- cause severe itching that can persist over time
- result in open sores caused by prolonged scratching
- cause sores to become infected and so itchy that they disturb sleep (in extreme cases).
Consult your doctor for advice on treating sores and reactions from the biting midge.
According to Queensland Health, midges do not transmit disease to humans in Australia.
Personal and household protection
Some steps may provide personal and local protection from midges.
Wear light coloured clothing, preferably long pants and long sleeves when outdoors. Wear these particularly in the early morning, late afternoon and into the evening.
Use insect repellents as directed. Consult your doctor on the suitability of insect repellents for short and long-term use.
There are two ingredients most commonly used. Check the list of ingredients on the can or bottle:
- diethyl toluamide (DEET)
The concentration of DEET will vary and it will be higher in the ‘tropical’ strength formulations. When the biting midge numbers are intense, higher concentrations of DEET would be more effective (somewhere around 15-20%).
Picaridin is the alternative active ingredient in some insect repellents. It has only been in use in recent years but is developing a good reputation.
You can deter insects indoors by:
- using ceiling and pedestal fans (midges don’t like air currents)
- spraying window screens with an aerosol to reduce numbers of midges coming through
- using 240 volt plug-in pads.
You can deter insects outdoors by using:
- mosquito coils
- small lanterns that have a tea candle burning under an impregnated pad (same active ingredient as mosquito coils but 100 times more concentrated)
- a product similar to the small lantern that uses a mini gas cylinder to heat the pad.
These products are for outdoor use only.
Barrier or harbourage treatment involves applying residual pesticide in the yard around your house. This treatment may reduce midge numbers for up to six weeks though not totally eliminate the pest. Apply the pesticide to shrubs, foliage, fences, house walls and screens.
Licensed pest controllers may use a product to do this. Its key active ingredient is bifenthrin, a synthetic pyrethrin.
There are also products available at the supermarket with bifenthrin. It is in ready to use one, two or three litre packs with a hand trigger. You must take care to follow the manufacturer’s instructions with these products.
This chemical treatment is indiscriminate and will kill most other insects over the six-week period that it is active. Do not apply to plants that are in flower and attracting other insects.
What Council is doing
Brisbane City Council is coordinating research to learn more about this pest and what caused the serious pest species C. ornatus to move to Brisbane. Council research about the midge includes:
- is it here to stay
- will it continue to spread
- are there more effective ways to protect households, work places and recreation areas without harming the environment
- is there an environmentally safe way to prevent it from breeding.
Council has been controlling mosquito larvae for many years using environmentally safe chemicals. However, Council cannot control the midge over broad areas as:
- there are no chemicals available or registered in Australia to control midge larvae
- the larvae live in mud in fragile ecosystems. Council would need to use unacceptably high concentrations of chemicals to penetrate the mud and control them.