Pink moths are opening markets for New Zealand apples.

A million of the sterile moths, both male and female, were imported this season for a pilot programme to control the codling moth in Central Hawke's Bay.

Over three years the programme has slashed its population by 98 per cent, and total elimination would improve New Zealand's export-market access.

Plant and Food Entomologist, Dr Jim Walker said the programme had lead to decreasing use of insecticide: "bit we've also increased our use of sex-pheromone technology disrupting the mating of codling moth".

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"The sterilised technique, on top of these other measures, is really an intention overall to control or eliminate the codling moth locally within these orchards," he said.

Sterilised in Canada, the imported moths were dropped by drone over orchards so the local population will invariably breed with the sterilised moths, drastically reducing the resident population.

"On a 100ha orchard – this orchard we are standing in – there was just one adult codling moth captured – male – all season in all of their pheromone traps," Dr Walker said.

As larvae, they are fed a red dye which gives their bodies a pink hue when pressured, for easy identification. 80,000 each week are chilled to 1 C to settle them down for the 36-hour flight over the Pacific Ocean.

Initially the release of codling moths caused harm to humans because the scientists released them by hand from mountain bikes requiring one-handed riding that resulted in too many crashes.

A remote-control fixed-wing plane was also used for the release but now a drone is taking over duties for greater precision.

The moth sterilisation technique has been approved by Biogrow, enabling an organic apple orchard to be incorporated in the Central Hawke's Bay trial.

Plant & Food Research Science Group Leader for Biosecurity, Professor Max Suckling said the technology could be rolled out further, especially if there was an incursion of a new pest.

"Biosecurity is massively important to the economy and something like the brown marmorated stink bug is likely to be worth hundreds of millions, if not billions of dollars, to the New Zealand economy - taking that money away from the people that are producing food," he said.

"It looks like the sterile insect technique might be able to be used against the brown marmorated stink bug as well."

The stink bug has recently been found in three Japanese car shipments and would attack grapes, kiwifruit, apples, citrus, stone-fruit, corn and many other valuable crops.

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