By KEN SAPWELL
RESIDENTS face a mosquito invasion triggered by ideal breeding conditions in parts of the Tweed.
Tweed council's entomologist Clive Easton warned yesterday that mature mosquitoes were expected to emerge in their thousands from many rain-sodden areas over the next few days. He said they included aggressive varieties known to carry the potentially debilitating viruses, Barmah Forest and Ross River.
Mr Easton said the council began aerial spraying of isolated wetland areas around Bilambil, Cobaki and Terranora last week in a bid to check breeding activity.
Staff had also spread a biological larvicide by hand in some areas considered too close to homes for an aerial attack.
But the council did not have enough time or resources to treat all potential breeding areas since last Monday's heavy rain.
As a result wrigglers which had hatched from long-dormant eggs were now expected to take to the wing over wide areas of the shire this week. Mr Easton said vast quantities of mature mossies had been able to survive because of the lack of fish and other predators in areas which have received rain for the first time in many months.
"The problem has been exacerbated by the drought which resulted in cattle grazing in wetlands and making it more difficult to control the mosquitoes," he said.
Mr Easton said the return to more humid weather was likely to increase the numbers of biting midges.
"The rain does not have the same impact on midges, but the higher humidity increases their flying range," Mr Easton said.
The North Coast Public Health Unit has urged residents to take precautions during the expected mosquito outbreak.
The unit's director, Greg Bell, said people should wear light-coloured loose-fitting clothing during the peak activity times in the early morning and late evening. They should also wear a roll-on insect repellant and use a knock-down spray at nights if their house is not protected by wire-screen windows.
Mr Bell said drought conditions had kept the incidence of Ross River and Barmah Forest virus down so far this year.
He said 95 cases of Barmah Forest had been reported so far this year, compared to 250 cases for last year, while cases of Ross River virus stood at 150, compared to 260 last year.