Latest Painted Apple Moth is a newcomer 

The Painted Apple Moth.

A Painted Apple Moth trapped at an Otahuhu, Auckland container facility early in May was a new arrival, and not a remainder of the population in West Auckland that sparked eradication measures in 2002, say Biosecurity New Zealand.

"While scientific testing using DNA had previously been difficult because of technical challenges, the recent use of a different gene region has proved successful, " said the organisation's biosecurity scientists.

"Additionally the use of a forensic tool being developed at Otago University was recently identified as an alternative option. The results from both testing regimes indicate that the male apple moth caught on 5 May 2005 was a new arrival."

Biosecurity New Zealand Eradication Programmes Manager Ian Gear said the latest testing compared the ratios of certain stable isotopes of the Otahuhu moth with previous captures in Auckland, Australia and with moths bred in the two colonies established to produce females as part of the Auckland eradication programme.

"Testing indicated the Otahuhu moth was significantly different to moths already in New Zealand, and most similar to the Australian moths. The results also indicated the Otahuhu moth had pupated in a climate significantly more arid than Auckland. Stable isotopes for the main Auckland population were reasonably consistent, but were significantly different to an Australian moth tested," said Mr Gear.

"As well as saying the Otahuhu moth is significantly different, the results for hydrogen and carbon isotopes in particular gave us some spectacular indications of the potential of the technique. Carbon isotope values indicate the diet of the larvae, and there were two clearly distinct groups. One indicated a diet of foliage; the other indicated the artificial diet fed to the colonies held in containment. It was possible to establish that the two colonies shared a similar diet, but had a different water source.

"It really is a useful technique that has great potential. While the information needed to indicate a definite point of origin is not available at this stage, it will be possible to build a database that will just about tell us the moth's suburb, street address and passport number," said Mr Gear.

The discovery will be a blow to MAF and the Auckland City Council, who have been jointly managing an eradication programme against the Painted Apple Moth in the city for several years.

Auckland City had claimed on their website that eradication of the Mt Wellington Painted Apple Moth population was thought to be "nearly complete".

- HERALD ONLINE STAFF