Invader wins - MAF quits moth battle

By ANNE BESTON

An Australian moth pest which attacks eucalypt trees is out of control in New Zealand.

The Ministry of Agriculture and Forestry said yesterday that it was abandoning attempts to eradicate the gumleaf skeletoniser.

It says the moth may have been in Auckland for up to seven years before it was discovered.

Lessons had been learned from the infestation, said MAF's director of forest biosecurity, Peter Thomson.

One was that a 1km survey zone set up two years ago should have been much wider.

It was also obvious that Auckland needed more biosecurity resources because it was a pathway for new pests.

The gumleaf skeletoniser has spread from Devonport on the North Shore to Wiri in South Auckland.

"It's particularly hard to spot and appears to have been spreading at low levels over that time," Mr Thomson said.

"But over the past year we've seen an explosion of the population."

The skeletoniser was eradicated at Mt Maunganui in 1997, but appeared in Onehunga in 2001.

It was thought to have been eradicated through spraying, but in February this year it was found to have spread throughout Auckland.

Councils and plantation growers will now have to pay to manage the moth, although MAF will help with money to find a biological control agent such as a natural predator.

The gumleaf skeletoniser feeds on the leaves of the eucalypt family, reducing trees to a skeleton.

The Farm Forestry Association's biosecurity spokesman, Denis Hocking, said the country's approximately 1000 eucalypt growers were disappointed with yesterday's decision.

People in cities would also be affected because the moth would attack many commonly grown ornamental and shelter trees.

The skeletoniser's brown, hairy caterpillar was a "nasty little critter", Mr Hocking said.

"It can cause severe irritation, and it's an unpleasant insect to have around the garden."

Gumleaf skeletoniser joins a growing list of alien pests which have breached New Zealand's borders. Others include the varroa bee mite and the guava moth.

NZ's pest invaders:


* 1990 Argentine ant - Auckland

* 1993 Redback spider - Auckland

* 1997 Gumleaf skeletoniser - Mt Maunganui

* 1998 Varroa bee mite - North Island

* 1999 Painted apple moth - West Auckland

* 1999 Banjo frog - Auckland

* 2000 Yellow flower wasp - Northland

* 2001 Kentia palmseed borer - Auckland

* 2002 Southern saltmarsh mosquito - Kaipara Harbour

* 2002 Avian poxvirus - Auckland

* 2002 Lettuce aphid - Christchurch

* 2002 Eastern flower thrips - South Auckland

* 2002 Asian kelp - Auckland