Microbats may combat mosquitoes

Gosford Council may encourage microbats to roost at Killcare in an attempt to reduce mosquito numbers.

Staff from the council's Environmental Education and Protection Unit (EPU) told the council that a number of microbats, including threatened species, were known to consume between 50 to 100 per cent of their total body weight in mosquitos over a night.

They had been recorded to consume up to 400 mosquitos an hour.

EPU staff told the council that microbats might be encouraged to recolonise areas where mosquitos were available, if residents provided additional roosting habitat.

The council was told that Ryde Municipal Council and the Sydney Olympic Park Authority (SOPA) conducted chemical mosquito control programs.

Both programs relied upon the application of larvicides to reduce the emergence of adult mosquitoes with the cost ranging from $70,000 per year at the Sydney Olympic Park to $10,000 at Ryde.

The EPU said broad scale chemical use such as larvicides in the control of mosquitos could lead to a detrimental long-term impact on the wetland ecosystem.

It warned council that other saltwater breeding areas and mosquito nuisances occured in the Gosford City area and similar responses might be expected from residents of those areas in the event of a mosquito management program being implemented.

The microbat approach would form part of a Mosquito Management Project, which would be the first on the Central Coast.

Council decided at its September 7 meeting to proceed with a comprehensive risk assessment of the Killcare area.

At Council's June 22 meeting, a petition with 383 signatures was tabled stating that there were excessive numbers of mosquitoes in the vicinity of Killcare and noted that a high proportion of these mosquitoes were the salt marsh mosquito, a known vector of disease.

The petition requested council's support in finding a solution to protect their health and lifestyle by controlling mosquito infestations with the use of eco-friendly controls.

Killcare resident Ms Sandy Robinson called for a study because she said it was becoming increasingly difficult to live in harmony with the mosquitoes.

"You cannot entertain outdoors. You cannot garden. Even driving to work, they are a hassle. You can't do anything," she said.

Ms Robinson said the mosquitoes came mainly for three months each year.

"I want to protect our health and lifestyle with eco-friendly controls," she said.

A comprehensive assessment of Killcare and expert advice on the relative nuisance values, health risks and acceptable and effective options from the Department of Medical Entomology would cost approximately $6000.

As part of the initiative, council would ask Central Coast Health to share the cost of the risk assessment.

Cr Craig Doyle said that Killcare was only one suburb out of 55 in the Gosford area, and if council agreed to this study there was "every chance" of an avalanche of requests.

He also said that the management of mosquitoes was an area generally not dealt with by council and more to do with the Central Coast Public Health Unit.

"I am worried that council will be responsible for everything that shakes or moves a tree," he said.

The Central Coast Public Health Unit advised in April that a mosquito surveillance site at Killcare was specifically monitored for salt marsh mosquitoes, as this variety of mosquito was an efficient and prolific vector for the transmission of Ross River and Barmah Forest diseases.

Lyle Stone, Council agenda DH.085, September 7