Fire ants join pest invasion

By ROSALEEN MacBRAYNE

Tropical fire ants have become the latest exotic insect to be identified in New Zealand.

A fire ant nest was found in a Port of Tauranga container yard at Mt Maunganui during a routine Ministry of Agriculture and Forestry inspection two weeks ago.

Last Wednesday, biosecurity staff discovered two yellow crazy ant foragers at the same yard. This is the first find in the Bay of Plenty, although a small nest of the yellow crazy ants was destroyed at the Ports of Auckland in April last year.

Colonies of crazy ants - a different variety - were detected twice in Auckland in April last year and at Mt Maunganui in January and March this year. They are thought to have arrived on timber from the Solomon Islands, Fiji and Papua New Guinea.

Crazy ants and yellow crazy ants, named for their fast, erratic movement, can cause severe irritation to humans and animals. The ants spit formic acid into the eyes of prey, causing blindness.

Tropical fire ants have a painful sting.

The Mt Maunganui finds were part of Maf's ongoing invasive ant programme, started in March 2001 following discovery of the nastier red fire ant at Auckland International Airport.

Programme coordinator Amelia Pascoe said early detection was the key to the eradication and control of invasive ant species.

Surveillance was focused on high-risk areas such as international ports, transitional facilities, container yards and some nurseries. Monitoring around sites where exotic ants had been found was on-going, she said.

Generally a site had to be free of ants for two years before Maf could be confident they had been eradicated.

As well as being a public health risk, invasive ants could potentially become predators of native ant species.

Aggressive Argentine ants, one of the world's worst insect pests, have been spreading through parts of New Zealand since 1990.

Late last week, Acting Biosecurity Minister Dr Michael Cullen told Parliament that New Zealand had had around 30 biosecurity incursions requiring eradication or control over the past five years.

The estimated cost of the pest invasions was $100 million.

His revelations followed an announcement that the fight against the gumleaf skeletoniser moth was to be abandoned.

The estimated cost of the war against the painted apple moth in West Auckland is $39 million so far.