East Asian harlequin ladybird raises concerns after sightings in Kaitaia

The harlequin ladybird has spread through much of the world and have been spotted in Kaitaia.

To most people a ladybird is a ladybird, but a new variety, originally from East Asia, has established itself in New Zealand. And now it has been spotted in Kaitaia.

Northland Age photographer Debbie Beadle said she was camping in the town earlier this month, and saw plenty of them.

The species does not present a human health issue, and does gardeners a favour by eating aphids, scale insects and mites, but they easily out-compete their native counterparts, which are slightly smaller, for food, and can be a major problem in vineyards.

The insects were introduced in the United States as a bio-control agent (targeting aphids) in 1988, and were released in Britain in 2004. There has been no deliberate release in New Zealand, but they were first found here in 2016, and are now widespread.

New Zealand Winegrowers' biosecurity manager, Dr Edwin Massey, said Hawke's Bay had been hit hardest, the ladybirds representing a potential source of wine taint.

"We know it is in all our wine regions apart from Waipara, in Canterbury, and Central Otago, but Hawke's Bay has been the centre of the largest populations that we have had notified to us through our growers' network," Dr Massey said.

"At the moment we are working with Plant and Food Research to undertake a surveillance programme there. (They) haven't been found anywhere in New Zealand aggregating on grapevines themselves, and that is great news for us, but it has been found in large volumes in sheds, pumping stations and other vineyard buildings.

"Last winter there was certainly a significant increase in the number of reports, particularly coming from Gisborne and Hawke's Bay, and we also had several from Nelson and Marlborough.

"This year we are expecting more again, because we have gone out with some strong messages around education and awareness.

"At this stage we still don't know a hell of a lot about what this ladybird means for the New Zealand wine industry. It has only been here for three harvests, and we certainly need to know more."

Reports of sightings would be "gold," he added.

Eradication of the insects, which sheltered inside buildings and cracks during the cooler months, was now highly unlikely, however, the best hope being to manage populations.

Meanwhile Biosecurity New Zealand recovery and pest management manager John Sanson defended MPI's decision not to do more to reduce the spread. The species was already well established when the ministry was first alerted to its arrival in April 2016.

"It was also determined that containing or slowing the spread was not feasible due to limited effective management tools being available," Mr Sanson said.

"MPI stood down the investigation, and has undertaken no further operational measures. We have however continued to liaise with the pip fruit and viticulture industries to provide information and support."

The MPI had received 18 emails and 88 phone calls about harlequin ladybirds so far this year.

There were a number of possible "pathways" for its spread, given its ability to "hitchhike" on equipment, and it was now being found in both the North and South islands.

The harlequin ladybird has spread through much of the world, including Europe, North America, the United Kingdom, Egypt, Kenya, South America, Russia, and most of South America.