A pilot programme undertaken by Plant and Food Research has seen thousands of sterile codling moths released into Central Hawke’s Bay apple orchards each week.
Their mission is simple: to mate with the local moth population, ensuring no new offspring are produced.
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,” said 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 added: “The codling moth is a major pest for apple growers. This organically accepted technique can help eradicate them, particularly when used in combination with other mating disruption techniques that many growers already use."
Tim Herman, Technical Manager of New Zealand Apples & Pears, said the industry was always looking out for innovative ways to control codling moth numbers in order to reduce its 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 could potentially prove effective for eradicating other insect pests, such as Queensland fruit fly, if the species became established in New Zealand.