Sterile fruit fly release in Cobram

By Cobram Courier

Queensland fruit fly populations in and around Cobram will be disrupted by the release of sterile flies as part of a national Hort Innovation project.

About two million sterile flies a week will be released across 16 square kilometres by a specialised small plane passing above Cobram in the next few months.

Sterile Insect Technique is a method of pest control using the area-wide release of sterile insects to reduce reproduction in a wild population of the same species.

The release aims to suppress an urban population to prevent it moving out into the surrounding horticulture.

Goulburn Murray Valley Regional Fruit Fly co-ordinator Ross Abberfield said SITplus complimented the co-ordinated approach to the area wide management of the pest undertaken as part of the GMV regional fruit fly project.

The release of the sterile flies is part of a multi-pronged strategy which includes surveillance trapping, baiting, removal of unwanted or unmanaged host trees and an extensive community awareness and education campaign.

The Hort Innovation project ‘FF17000- Post Factory Pilot of SITplus fly production’ is led by Macquarie University in collaboration with South Australian Research and Development Institute, Agriculture Victoria, NSW Department of Primary Industries and Plant and Food Research.

Cobram was selected as a release site due to its existing intensive trapping grid, the proximity of horticulture to the town and support for the project from growers, Moira Shire Council, Berrigan Shire Council and the regional fruit fly project.

The sterile flies are grown to the pupal stage in Port Augusta, then sterilised at Netley, before being shipped to special rear-out facilities in NSW and Victoria where the sterile adult flies emerge from the pupal case and are ‘conditioned’ ready for release. The Victorian rear-out facility is at Tatura.

The first sterile pupae arrived in Tatura today and the first release of sterile flies is planned for March 20, provided weather conditions are suitable.

The plane releasing sterile flies will make a limited number of passes above the Cobram urban area in a single flight, once a week during March until the end of May.

Sterile flies will be colour-coded by presence of a special dye visible under ultraviolet light, to distinguish them from wild flies in traps.

Additional traps will be installed around the drop zone to study the dispersal of the sterile flies and help scientists more accurately estimate the size of the wild fruit fly population.

This is important for future releases of sterile flies because the ratio of sterile flies to wild flies needs to be high enough to successfully compete with and disrupt the breeding of wild flies.

The SIT method was employed to combat the impacts fruit fly on Australian horticulture through the creation of the SITPlus partnership in late 2014.

Further releases will take place in Cobram in spring as wild flies become more active.

SITplus is one aspect of fruit fly control and prevention and the community, growers, industry and government agencies are reminded to remain vigilant in undertaking steps and actions to help reduce the spread of fruit fly.