Fruitless sex is collapsing codling moth populations

A pilot programme to collapse the population of one of New Zealand’s most harmful apple pests, the codling moth, has produced spectacular results, Plant & Food Research reports.

Each week thousands of sterile codling moths are being released into Central Hawke’s Bay apple orchards to mate with the local population. Critically, no progeny are produced from these relationships, although the sterile moths have the same drive to mate.

By overwhelming the local codling moth population with the sterile moths, imported from a production facility in Canada, the wild moth populations have collapsed.

Of particular importance to the programme is the method for releasing the sterile insects. An unmanned aerial vehicle (UAV), following GPS coordinates, is fitted with special pods that release 20,000 sterile moths over 100 hectares of orchard during a flight of just 10 minutes.

These releases mean there may be up to 200 sterile moths for every fertile moth present in the treated orchards.

“We’ve seen dramatic results across the 400 hectares of Central Hawke’s Bay orchards treated with these sterile moths, up to 98% reduction of the wild moth populations,” says Plant & Food Research scientist Dr Jim Walker.

“Within two seasons we expect the codling moth population will be eliminated from these orchards.”

Plant & Food Research Science Group Leader Professor Max Suckling says this organically accepted technique can help eradicate a major pest for apple growers, particularly when used in combination with other mating disruption techniques that many growers already use.

Tim Herman, Technical Manager of New Zealand Apples & Pears, says the New Zealand apple and pear industry is always looking for new and innovative ways to control codling moth to reduce the use of insecticides.

“We already produce fruit with very low residues, but this research will add to our already sustainable programme of codling moth control and help maintain our ranking as the most competitive apple and pear industry in the world.”

It is believed that the same method has the potential to prove effective for eradicating other insect pests, such as Queensland fruit fly, if the species became established in New Zealand.

Click HERE to see a video of the UAV in action

Source: Plant & Food Research

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Scientist honoured for outstanding contribution to NZ’s pipfruit industry

Plant & Food Research scientist Dr Jim Walker has been awarded the New Zealand Apple and Pear industry’s Outstanding Contribution Award.

New Zealand Apple and Pear board member Peter Beaven presented Dr Walker with the award at the industry’s annual conference in Napier and noted his long service and significant impact.

Mr Beaven said Dr Walker was the brains behind the Integrated Fruit Production programme introduced in the 1990s.

The programme was a world first and a huge departure from the then current practice around the world.

“With IFP, growers started monitoring the numbers of harmful insects on orchards through pheromone trapping and introduced the use of targeted selective sprays when required,” Mr Beaven said.

“The IFP system was introduced across the entire industry in a remarkably short time due in no small measure to this man’s efforts. Today we take such systems for granted.”

Dr Walker was also instrumental in the next generation of orchard management – the Apple Futures programme, which further reduced residue levels on fruit and enabled the industry to tailor production systems of blocks within orchards to meet the phytosanitary and residue requirements for specific markets.

“However, I rate Jim’s most significant contribution to our industry as making science easy to understand for non-scientists. The best science is useless if growers cannot understand it or know how to apply it in a commercial setting. Jim has always had the knack of explaining things in ways we laypeople can readily grasp”.

Dr Walker said he was honoured to be the award recipient – and he is not yet ready to retire.

“I have been really proud to serve this industry which I have been involved in one way or another since 1972.

“I’ve worked in the industry for almost 45 years and I’m not ready for the ‘R’ word so I’m not retiring but will be reducing my hours. It’s been great to work within an outstanding industry, with outstanding growers and it has been an amazing opportunity.

“I have been part of a team of people and although the success of the IFP programme is often tracked back to one individual, it has been a bigger team that have helped along the way such as my colleagues at Plant & Food and at DSIR before that.”

Dr Walker said highlights have been seeing growers achieve a 90 per cent reduction in pesticide loading (per hectare); the elimination across the apple industry of the use of former ‘highly toxic’ insecticides; about 35 per cent of the industry now using non-insecticidal ‘mating disruption’ techniques (i.e. sex pheromones) and the lowest possible pesticide residues on IFP (NZ) apples in international markets, a similar risk profile to organic apples.

“A lot of the work has been fun, working in the discovery and developing of the concept of multiple species as a distribution system. I can see grown men chuckle when we talked about tethering virgin female moths and putting them out in orchard to see if they will get discovered by males in the presence of all of the pheromone out there,” he said.

Dr Walker said another highlight was gaining access for apples into Australia, although there is still work to do in getting meaningful access.

The past, present and future of integrated pest management in fruit crops

Pests and the use of pesticide to deal with them have long been a problem for the New Zealand Pip Fruit industry, especially when it sought to gain access into new, high-value export markets.

But work carried out by Dr Jim Walker and his team has contributed to a reduction of more than 90 per cent in insecticide use (kg/ha) by local apple growers since the mid 1990s.

Alternative strategies have included the introduction of new natural enemies through to the development of selective pest management and use of semio-chemicals (pheromones) to support greater use of biological control in apple orchards.

The development and implementation of these innovative pest control measures are now central to today’s pest management systems.

Dr Walker, entomologist and Principal Scientist with Plant and Food Research, will talk about this research as well as the future sustainability and biosecurity threats facing the apple industry in Havelock North at 5.30pm on Wednesday..

Readers can register here to guarantee a seat

WHERE: Havelock North Function Centre, 30 Te Mata Road, Havelock North, Hawke’s Bay.