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Ongoing project

Pilot sterile codling moth releases for the apple industry (AP18001)

Key research provider: Tasmanian Institute of Agriculture

What’s it all about?

This investment is investigating the feasibility of using ‘sterile insect technology’ (SIT) in the control of codling moths in Australian apple orchards.

SIT has been used in parts of Canada to reduce wild moth populations and pesticide use, and is also being trialled in New Zealand. The approach involves producing sterile male codling moths, which are developed to be fit and attractive to wild females. Released into orchards, the sterile moths compete for females, helping stop the wild moth population from successfully breeding.

Following this project’s feasibility investigation, pilot releases of sterile codling moths will be used to assess the effectiveness of the approach in controlling wild populations, and to develop guidelines and recommendations for incorporating sterile moth releases into existing pest management programs across the country.

Sterile codling moths imported from Canada were released on a weekly basis throughout the fruiting season, with the final release for the season in mid-February 2023. Weekly trap monitoring at both the release and control sites continued until mid-March 2023, one month after the final release. Quality tests have been conducted on three consignments of moths over the season. At each control and release site, fruit were assessed for codling moth damage prior to harvest and trunk band traps installed for monitoring of over-wintering larvae, However this data is still being processed. 

In the November/December period, the ratio of sterile:wild moths remained below 5:1. This coincided with a two-month period of cold, wet weather, which may have reduced the survival and suppressed the activity of the released moths.

Captured sterile moth numbers increased rapidly from mid-January while wild moth numbers declined, with the sterile:wild ratio lifting consistently above 10:1 and over 150:1 in some weeks.  There was a positive association in sterile moth catches with the average maximum temperature and a negative association with the total rainfall in the week preceding each trap catch.

Releases will recommence in October 2023.

A trial shipment of sterile codling moths (SCM) imported from OKSIR (Canada) was organised for late September 2022 to ensure that any issues along the supply chain were sorted out prior to the weekly shipments destined for release. The project have developed a working protocol and shipments are being received on a weekly basis, however quarantine clearance often delays pickup of the shipments by up to 16 hours. Weekly SCM shipments for field releases commenced on 26th October 2022 and will continue through to mid-February 2023. 

Codling moth traps have been installed at all release and control sites and are monitored weekly to determine wild and sterile moth populations.

The project is now back on track following two years on hold due to the COVID-19 pandemic. The import permit was approved in April 2022, and the conditions of the permit allow for the importation of Cydia pomonella (Codling moth) which have been sterilised by gamma irradiation treatment at the Okanagan-Kootenay Sterile Insect Release (OKSIR) facility, located in Canada. Imported material can only be used for direct release into the environment for biological control use and is limited to the apple orchard field sites in South Australia and Tasmania that are part of the sterile insect release research program.
Now that flight timetables are becoming more reliable, small trial shipments of sterile codling moths are being organised with OKSIR to ensure that freight logistics and biosecurity control at both national and state borders are sorted prior to the field releases that are scheduled to begin in November.

Related levy funds

This project is a strategic levy investment in the Hort Innovation Apple and Pear Fund