Year-round wet weather and a recent rise in temperatures means mosquitoes and midgies are out in force in the South East as area councils join forces on an ambitious spraying programme.
- A rainy year and recent high temperatures have caused an explosion of mosquitoes and midges
- South East Queensland councils have launched a task force to target mosquito breeding areas
- Residents should cover and remove water sources in the home to prevent insects
Brian Johnson, senior research fellow at QIMR’s Berghofer Mosquito Control Laboratory, said the explosion in the irritating and sometimes painful insects comes down “mostly to water and heat.”
“We’ve had a lot of moisture recently and we’ve finally had some warm days in the last two weeks and it only takes a week or two for the insects to respond to that,” Dr Johnson said.
“Our current control measures target mosquitoes in their larval habitat and are the most effective means of mosquito control.
“Now there are more efforts to control freshwater mosquitoes.
“A lot of micro-habitats are created in these wet conditions, so it’s very difficult to target all areas, and there will be some areas that may escape.”
Queensland Museum entomologist Chris Burwell agreed that insects and other animals had “three fantastic years”.
“Not in terms of flooding, but … a lot of rain means a lot of plants and insects,” Dr Burwell said.
“Rain is just a sign that good conditions are coming.
“Typically the winter months are colder and not good for insects because they can’t generate their own heat.
“Winter months are generally drier.
“Spring rains signal plant growth and warmer temperatures.”
The task force is targeting the mosquito problem
Brisbane City Council staff began targeting thousands of mozzie breeding sites last week in a bid to prevent a major outbreak after the latest bout of wet weather.
Lord Mayor Adrian Schrinner said 2,400 locations across the city had been targeted by spraying.
“It was raining early this morning and obviously rain means puddles, which means mosquitoes and especially freshwater mosquitoes at the moment, so we’ve got teams out all over town,” he said.
“Right now we’re doing it by ground, and when there’s a trigger for saltwater mosquitoes, we’ll do it by air.
“Wetlands are our target areas, but there are places all over the city [where mosquitoes breed]you’d be surprised.”
With two entomologists on staff, the council leads a south-east Queensland mosquito taskforce set up to help manage Japanese encephalitis virus at a regional level.
“Some councils don’t really have dedicated mosquito spraying programs so we work with them because mosquitoes don’t know local government boundaries,” Cr Schrinner said.
According to him, the first meeting of the group was held on Monday night.
A spokesman for Logan City Council said “760 water storage areas” had been cleaned, while Redland City Council introduced a “year-round mosquito control programme”.
Midges descend on the suburbs
Anecdotally, there have recently been many complaints of midges – small, biting, blood-sucking insects – appearing in areas south-east of Brisbane where the creatures are not normally encountered.
Dr Johnson said he had heard cafe patrons complain about the runoff and said the ones hanging around backyards and bush blocks away from the mangroves were a species that grew in moist, leafy areas.
“These are not midges associated with intertidal zones,” he said.
“These species breed away from the coast, in suburban waterways or just in some muddy areas and patches around properties.
“We have plenty of moisture for them, but now the heat has contributed to the population explosion.”
Midges and mosquitoes
As many people who live in subtropical and tropical parts of the country will attest to, even though the insects are smaller, midge bites are more painful and cause a greater reaction than mosquito bites.
Dr. Johnson likens the midge’s extraction of human blood to “a dog licking a dish.”
“Midges have mandibles that are like little razor blades, and they have to cut the skin and suck up the blood,” he said.
“It’s kind of like a dog licking a bowl, and so they spit a lot of saliva into the wound.”
Babies or young children who are not used to midge bites will have a more severe reaction to the insects than adults, Dr Johnson said.
Unlike mosquitoes, midges were difficult to combat with environmentally safe insecticides.
Dr Johnson said midges spent most of their lives in the mud. He said heavy chemicals would be needed to target them, a strategy that would have devastating effects on the surrounding wildlife.
How to prevent insect bites
Cr Schrinner said while councils continued to treat mosquito breeding areas, residents could protect their homes, families and pets from mosquitoes in a number of different ways.
“The council treats the larvae before they turn into adults and leave their breeding grounds – and we treat every chance we get,” he said.
“When adult mosquitoes are active, residents should use insect repellent, wear loose, full-length and light-colored clothing, and limit time in mosquito-prone areas, especially during the evening and early morning hours, to help reduce the risk of being bitten.
“Residents can prepare their homes for mosquito season by keeping their yards clear of water-holding containers such as buckets, potted plants, saucers and birdbaths.
“Make sure windows and all gaps in rainwater tanks are screened, and make sure roof gutters aren’t blocked by leaves.”
Dr Johnson agreed that “source reduction” around homes is “everything you can do” to limit mozzie and midge infestations.
“Other than that, it’s really hard,” he said.
He said traditional repellants like Bushman or Aerogard, and natural repellants like citronella and eucalyptus oil are effective, but they need to be applied more often.
Dr Johnson also said that while Aussies are used to being bitten by insects, the public needs to follow a Slip, Slop, Slap campaign to protect themselves from mosquito-borne diseases and general nuisance.