Being aware of mozzies if irrigating

19 March 2009

MAF Biosecurity New Zealand (MAFBNZ) is asking property owners in the Wairau area of Marlborough to be aware that if they are planning irrigation, there is a chance they may cause hatching of Southern saltmarsh mosquitoes.

The biosecurity agency is currently running an eradication programme to rid Wairau of the pest mosquito – a vicious day-time biter known to carry the Ross River virus in Australia.

MAFBNZ Incursion Manager David Yard says the treatment programme is progressing well, but it's important to realise that the introduction of standing water, such as through irrigation, could cause any viable mosquito eggs that may remain in the area to hatch.

"We are really keen for landowners considering irrigation in the immediate Wairau treatment area (between the Vernon Lagoons and the Kidney Ponds north to the Wairau Diversion) to contact our contractors to seek advice and ensure that the elimination programme is not compromised," says Mr Yard.

"There is no reason why irrigation can't be carried out, but it is helpful that we know where and when it's taking place so that we can monitor these areas closely for any outbreaks."

The contractor undertaking the treatment in Wairau is FBA Consulting and they can be contacted on: 027 448 8168.

The Wairau eradication work involves helicopter and ground treatments, trapping and sampling. Treatment is carried out every three weeks using s-Methoprene granules - an insect growth regulator that stops mosquito pupae from hatching into adults.

Mr Yard says there have been no finds of mosquitoes or their larvae in the Wairau region since June 2008.

"We hope to be able to declare the elimination of the Southern saltmarsh mosquito in Wairau in July 2010.

The only remaining area under treatment for the Southern saltmarsh mosquito (apart from Wairau) is in Coromandel. Localised outbreaks of the mosquito have already been successfully eliminated by MAFBNZ and the Ministry of Health in other areas such as Kaipara, Grassmere (in Marlborough) and the Hawkes Bay.

For further information, please contact: