Local Focus: Millions of pink moths coming to backyards

Plant & Food Research is engaging with Hawke's Bay households as it seeks to rid the region of codling moth, looking to deliver millions of the insect from drones.

The codling moth threatens New Zealand's ability to access overseas markets for apples and pears. But while it is actively controlled in orchards, codling moth has been found throughout Hastings gardens.

The widespread discovery was thanks to residents allowing 200 pheromone traps to be set, which captured twice as many moths per week compared with traps on commercial export orchards.

Codling moths were caught in all traps placed in gardens and surrounding walnut trees, which also attract the moths.

"Home gardeners unknowingly harbour codling moths on their apple and walnut trees because many of them don't have access to a codling moth management regime," Plant & Food research scientist Max Suckling said.

"These unmanaged host trees pose a threat because adult codling moths could fly several kilometres and potentially infest commercial orchards. It shows that the community needs to be an integral part of an area-wide pest eradication programme."

In a related study 86 households were surveyed on attitudes towards suppressing codling moth using the sterile-insect technique. The technique releases pink sterilised codling moths en masse from aerial vehicles, to interrupt wild codling moth reproduction.

In a successful trial in Central Hawke's Bay, millions of sterilised moths were dropped from a drone, slashing the codling moth population by 98 per cent.

They were bred in Canada and had been fed pink food so they could be easily identified if squeezed.

The survey showed 98 per cent of respondents would support the sterile technique for codling moths or, should they be found in the area, for exotic fruit flies.

Suckling said if the trial was to be rolled out regionally the insects could be bred in Hawke's Bay, but residents would only rally behind the chemical-free biocontrol if they were involved in the consultation process.

He said to achieve wide-spread eradication of codling moths, options included integrating the sterile technique with bio-control agents and the removal of host trees near orchards, except for iconic neighbourhood trees.

All methods in residential areas would require community consultation and it was hoped Hastings could provide a successful model for nationwide eradication of pests in a "smarter and more sustainable way".

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