Fruit fly findings near

02:04, Jan 24 2014
fruit fly
Queensland fruit fly.

First results should be known tomorrow from extra surveillance traps being set up in Whangarei following the discovery of a Queensland fruit fly.

The insect poses a threat to the country's $4 billion horticulture industry.

The alarm was raised after a sole male Queensland fruit fly was found in a surveillance trap on Tuesday and identified on Wednesday.

Controls on the movement of fresh fruit and vegetables have been put in place within 1.5 kilometres of the spot where the fly was caught. Even tougher controls are in place in a zone within 200 metres of the spot.

Extra surveillance traps will be set up in the 200-metre zone by the end of today.

First results from those traps were expected late tomorrow, after they had been in place for 24 hours, the Ministry for Primary Industries said.

Normally about 20 surveillance traps would be in the control area. They were being bolstered by about 200 additional traps, MPI deputy director general compliance and response Andrew Coleman said.

The pheromone-baited traps were the best way to find if any more male flies were in the area, but trapping was less reliable at identifying whether female flies were present.

To find out if any females were in the area fallen fruit would be gathered and each piece would be cut into 3-millimetre slices, with every slice analysed under a microscope for eggs or larvae.

The analysis would be done in a portable containment laboratory taken up from Auckland, which was expected to be fully operational tomorrow.

By late morning today, no more of the Queensland fruit flies had been found, Coleman said.

"The likelihood is that if there are any more, they most probably will be within the 200-metre zone. There's a possibility if there are any more they maybe within the 1.5km zone.

"Most unlikely that they would ever be beyond that because of the way that fruit flies live."

Efforts would be made to try to identify how the fly caught in the trap came to be in the area, but it might not be possible.

It might have come in through a marina for yachts from overseas, which was not far from where the fly was caught. It could also have come in through Port Whangarei, or arrived with fruit and vegetables being transported within the country.

The only thing regarding the origin of the fly that officials were confident about was that it was likely to have come as an egg or larvae in fruit or vegetables. It would not have been in the insect's pupae stage, because the fruit fly burrowed into the ground in the larvae stage and became pupae while there, Coleman said.

Fallen fruit was the likely host, as that was the likely place for pupae to go after coming out of the ground. Fruit and vegetables sold in supermarkets were picked before falling and so were unlikely to be the host.

An adult fruit fly was most unlikely to have survived a trip by boat across the Tasman, which could take between a week and 10 days.

A two-week period without any other indication of the flies being present - from Wednesday's confirmation the insect had been caught - was needed for New Zealand to be able to retain its status as being free of the Queensland fruit fly.


Whangarei fruit fly controlled area
LOCK-DOWN: A map of the controlled area where the fruit fly was found.

Fairfax Media