Mosquito larvae found in Kaipara region

15 December 2005

Mosquito larvae found in Kaipara region

The discovery of two southern saltmarsh mosquito larvae at a site in Kaipara signals another milestone in the attempted eradication of the Australian invader from the region.

Ministry of Health's contractors NZ Biosecure have been carrying out an intensive search to find mosquito breeding sites following the discovery of a lone adult southern saltmarsh mosquito in Kaipara in early November.

Ministry of Health Deputy Chief Technical Officer (Health) John Gardner has confirmed search teams found two southern saltmarsh mosquito larvae at a site 12km north of Parakai last Friday.

Mr Gardner said the larvae find was "good news" as it meant a targeted treatment programme could now be initiated to eradicate the breeding site. This will be done through the delivery of a control product called S-methoprene, which will be dispersed by both helicopter and ground vehicle.

The southern saltmarsh mosquito is highly sensitive to S-methoprene, which is an insect growth regulator. Mr Gardner said the control agent has been used successfully for mosquito eradication before in New Zealand and has met all environmental regulatory standards.

"It appears these larvae could be the last remnants of a population that had been previously treated. It would be imprudent to assume this breeding site is the only one and the intensive surveillance will continue at Kaipara Harbour. This will be done using adult trapping and larval search teams, with a special emphasis on habitats that have been identified as being a high risk," said Mr Gardner.

"Much of the habitat has remained dry and we are still waiting for a significant water event (high tide and rainfall) to occur that should flush out any southern saltmarsh mosquito eggs that might still exist at other sites."

Mr Gardner said all affected landowners had been contacted in person and informed further treatment of habitat on their land would be occurring. Consultation has also been carried out with the Department of Conservation, Iwi, the Residents and Ratepayers Association, Auckland Regional Council and other stakeholders.

Under World Health Organisation protocols the Ministry of Health will be able to claim eradication of the southern saltmarsh mosquito from the Kaipara region once it has detected no mosquito biomass in the eradication zone for two years.

ENDS

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