Fruit fly makes growers 'nervous as hell'

A single male Fruit Fly found in the Hatea Drive area of Whangarei. Photo / Ron Burgin

The discovery of a male Queensland fruit fly in Whangarei has sparked a major biosecurity alert.

Up to 50 Ministry for Primary Industries (MPI) staff were in the city and another 50 in Wellington were preparing yesterday to deal with the pest threatening New Zealand's $4 billion horticulture industry.

The fly was found in the front yard of a home near the Whangarei Town Basin on Tuesday. It was collected from an insect trap MPI had placed there as part of its national fruit fly surveillance programme involving 7400 traps around the country.

MPI staff yesterday put up signs banning people from taking whole fresh fruit and vegetables out of a 200m zone circling the place where the fly was found. Bins have been provided for residents to dump fruit and vegetables rather than disposing of them with other household rubbish.

Today MPI officials will begin putting about 200 pheromone traps into fruit trees in that zone and within a 1.5km radius of the discovery site extending up to the Regent, along Riverside Dr and into Parihaka.

An MPI mobile laboratory arrived in Whangarei yesterday for use analysing fallen fruit and vegetables to be gathered from the two zones.

Queensland fruit fly is one of the most damaging fruit fly pests because it infests more than 100 species of fruit. Some countries will not import fruit and vegetables from sources where the fly is known to exist.

MPI deputy director general compliance and response Andrew Coleman said yesterday that New Zealand's trading partners had been notified of the Whangarei find and measures were under way to find out if there is an infestation.

If no further evidence of fruit flies was found within a fortnight then overseas markets would accept the insect was alone, he said.

When the Northern Advocate asked whether the location of the fruit fly found in Whangarei indicated the insect had arrived in one of the many overseas yachts berthed at the Town Basin, Mr Coleman said it may have done.

"But we may never know how it got here," he said, explaining that the fruit fly life cycle involved a pupae development period in the ground.

The pheromone traps containing female fruit fly sex scent are expected to detect any males. If an infestation was found, ground spraying would be carried out to eradicate the invaders.

Minister of Primary Industries Nathan Guy and MPI chief executive officer Martyn Dunn were in Whangarei yesterday to see the fruit fly measures being imposed and for talks with Whangarei MP Phil Heatley, Mayor Sheryl Mai and top Northland Regional Council officials.

Mr Heatley said later the minister had assured Whangarei people there would be no aerial spraying such as the Ministry of Agriculture and Forestry carried out with the insecticide Foray 48B over parts of Auckland from January 2002 to May 2004 to eradicate another exotic pest, the painted apple moth.

Kerikeri Fruitgrowers' Association chairman Rick Curtis said growers in his area were "nervous as hell".

"They are watching and hoping the male fly found was alone," he said.

Fruit fly facts:

• The Queensland fruit fly is a native of Australia where it is considered to be the country's most serious insect pest of fruit and vegetable crops.

• The fruit fly has been detected three times before in New Zealand - in Whangarei in 1995 and in Auckland in 1996 and 2012. In all cases increased surveillance found no further sign of the pest.

• Air and sea passengers are prohibited from bringing fresh fruit and vegetables into New Zealand.

• Fruit flies eat ripened fruit and vegetables. Eggs which female fruit flies lay on fruit hatch into larvae which find dark places where they grow six legs and wings before emerging as adults.

• Larvae of fruit flies develop in moist areas where organic material and standing water are present. The entire life cycle lasts 25 days or more depending on the environmental conditions and the availability of food.