Growing the world’s best apples is a team effort. Plant & Food Research has engaged households in Hawke’s Bay, the heart of New Zealand’s apple industry, in studies that will
help create smarter and more sustainable ways to protect the prized fruit and those whose livelihoods depend on it.
New Zealand is the only country which can export apples to some of the world’s most exclusive and premium markets such
as Japan. To maintain the status, our apple exports must be free of pests like codling moths as well as contain low
chemical residues. Thanks to decades of innovation and integrated pest management practice, the codling moth population
on-orchard is largely under control, but the industry is not necessarily out of the woods.
Plant & Food Research scientists and their research partners at the University of Auckland have obtained permission from
households in Hastings City, a peri-urban (semi-rural) area close to commercial apple orchards, to install 200 pheromone
traps on residential properties. Some of these households have apple and walnut trees in their gardens – both common
host trees of codling moths. These traps have captured twice as many moths per week compared to traps on commercial
export orchards, and codling moths were caught in all the traps placed on host trees.
“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,” says Professor Max Suckling, member of the research team. “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, researchers have surveyed 86 households in Hastings in person on their perception of suppressing
codling moth using the sterile insect technique (SIT), which releases sterilised codling moths to mate with their wild
counterparts to break the reproduction cycle.
They found that upon explanation and clarification, an overwhelming 98% of respondents are supportive of the use of SIT
for codling moths, or for exotic fruit flies should they be found in the area. They were also in favour of the dispersal
of these sterilised insects using unmanned aerial vehicles such as drones. Almost all respondents welcomed researchers
setting up pheromone traps on their properties and conducting regular visits to collect data.
“Historically, the peri-urban community has not been well informed about orchard activities like spraying, which has
created an aversion to the use of insecticide sprays. These studies show that local residents could rally behind the use
of novel, chemical-free biocontrol methods as long as they are involved in the consultation process and their concerns
such as camera use and the impact on their family’s health are addressed,” Professor Suckling says.
He adds that to achieve area-wide eradication of codling moths and other exotic pests, options include widening the
scope of SIT to cover peri-urban areas, an integration of SIT with classical biocontrol agent and the removal of host
trees near orchards. Community engagement is crucial to guide practitioners in determining suitable technologies that
are beneficial to growers and acceptable to the locals.