Biting midges - Redland City Council

Biting Midges
Biting midges are insects frequently miscalled 'sandflies' in
coastal areas possibly because they are the size of a grain
of sand. Actually the sandfly is a different insect. Biting
midges are small (1-3 mm) robust looking flies that are
difficult to observe with the naked eye.
There are over 271 species of biting midges in Australasia.
Midges are an important part of our ecosystem. They
contribute to biodiversity and are a food source for many
aquatic organisms. They are not known to transmit any
human disease in Australia.
Only female midges bite. They make an incision into the
skin for blood to fertilise their eggs. The midge injects
saliva to ensure blood flow, which reacts with mammals
and causes irritation.
Biting midges find their prey by detecting exhaled carbon
dioxide. They are also attracted to sweat.
Tidal areas with dominant mangrove vegetation and
slightly acidic, loamy soil are likely to produce biting
midges. They live in foliage as protection from the wind.
The ‘pest range’ is the distance from midge breeding sites
where they are in high enough numbers to be considered a
pest—estimated to be 300 metres to one kilometre.
Dawn and dusk are the peak, active times for biting
midges, although they will bite all day in humid, still
conditions. Their activity increases just after new and full
moons.
Reaction to midge bites may vary from a slight redness
that disappears in half an hour or less, to severe
inflammation. If you react quickly and the swellings are
small, you are probably immune. If you react hours or days
later, you have low immunity. Immunity to midge bites
increases over time, but the early reactions can cause a lot
of discomfort.
What is Council doing?
Council does not treat biting midge sites because
the treatment has an adverse effect on the
environment.
We have conducted a study into biting midges in
the Redlands to identify breeding sites, what
species are here and the feasibility of various
control options.
What you can do
Personal protection
Wear light coloured, loose fitting clothing with long
sleeves and long pants. When gardening wear a
hat and gloves.
Use an inspect repellent. The most effective are
those containing DEET. For people who are
sensitive to repellents, equal parts of baby oil,
Dettol and eucalyptus oil make an alternative
repellent.
Have a hot bath and use anti-itching creams to
reduce the effects of bites
Avoid outside activities during the peak times of
dawn and dusk and the full and new moon
A dose of 200mg of vitamin B1 twice a day with
meals starting two weeks before exposure is
thought to increase immunity to midge bites.
Around the home
Reduce humidity and increase light and air movement
in your home and garden. Minimise water lying around
in the garden, keep lawns well mown, have sparse
vegetation and use fans inside the home.

Midge-proof mesh is available to screen doors and
windows. At peak times it may also be useful to spray
screens with a low toxic surface spray. Doors should open
outward to reduce the chance of midges following people
inside.
Light-proof curtains can reduce the number of midges
attracted to homes at night.
Close off the sheltered side of the home during peak times
as this is the side midges will enter.
The natural insecticide pyrethrum, available from nurseries
and hardware stores, can be used around the home and
garden. It has little residual capacity so regular weekly
applications will be needed.
Organic insecticides can be used. These are best used on
external walls or vegetation to create a barrier.
Paraffin oil or perfumed lamp oil mixed with citronella or
lavender oil burnt in lamps and placed upwind of outdoor
activities may help to keep midges away.
For more information contact Health & Environment, Redland City Council, PO Box 21, Cleveland QLD 4163,
Telephone (07) 3829 8999 or visit our website www.redland.qld.gov.au.
RCC 04/2009 - FS154
Useful organic insecticide formulations
Garlic spray
85g unpeeled garlic
2 tablespoons mineral oil
7g soap dissolved in 600ml water
Mix solution and use in a trigger spray bottle.
Derris spray
120g soap dissolved in 4.5L of water
60g derris powder (available from garden suppliers)
4.5L water
Dilute entire mixture in 12L of water. Mix and use in a
trigger spray bottle.