Codling moth (Cydia pomonella) is a key pest in most pome fruit production regions worldwide, including Australia where it is considered one of the most economically damaging pests in many production regions. Given that chemicals used for moth control disrupt beneficial insects, substantially affecting integrated pest management (IPM) systems, this project examined the application of Sterile Insect Technique (SIT) as a tool for control of codling moth in Australian apple orchards. 

Challenge 

Codling moth is considered one of the most economically damaging pests in many production regions in Australia where apple and pear production is valued at $647 million. If unchecked, it can damage 50 to 90 per cent of fruit, resulting in decimation of the industry. Other industries affected by codling moth in Australia include cherry, summer fruit, nashi and walnut.  

Management strategies to date include chemical control, phenology modelling, regular monitoring, mating disruption and biological control, but chemicals used as part of codling moth control programs disrupt beneficial insects, substantially affecting IPM systems. Codling moth has also developed some resistance to insecticides, making it more difficult to control. 

Canada has been successfully applying SIT for codling moth control within an area-wide approach in southern British Columbia for more than 20 years. Relative to pre-program levels, codling moth populations have been reduced by 94 per cent and fruit damage to less than 0.2 per cent in more than 90 per cent of orchards in the release area. 

Response 

The pilot project was established to: 

• Review the current status of codling moth in Australia
• Examine the application of SIT as a tool for control of codling moth in Australian apple orchards
• Establish release sites to determine the efficacy of sterile codling moths in control of wild populations
• Determine the feasibility of integrating SIT into existing apple and pear management and production programs in Australia.   

An economic analysis compared the costs and economic benefits achievable between SIT, mating disruption and agrichemical use, to inform grower and industry uptake of the technology. Findings from this analysis indicate that gross orchard gate income per hectare is expected to be higher under SIT relative to mating disruption (+$277) or pesticide use only (+$2295). These figures indicate SIT represents an approach that is economically beneficial for at least some growers if moths can be sourced and released locally, but that this quickly becomes unaffordable due to the increased freight costs and import charges if moths must be imported from Canada.  

While it is technically feasible to import sterilised codling moths from Canada, it is too unreliable due to inconsistency of shipments throughout the season and the long transport chain (60+ hours). However, if the sterile moths could be sourced from within Australia it would seem reasonable to expect that the levels of codling moth control achieved and economic returns to growers would be viable.   

Benefit 

This pilot program has successfully investigated safe and secure biosecurity pathways for entry of sterilised codling moth into Australia from Canada, developed and tested the logistics of transport and release, and examined the costs and feasibility of success.  

The project has demonstrated proof of concept for the use of SIT as a tool for control of codling moth with reduced fruit damage at two test sites.   

Commercialisation and adoption of SIT for use in commercial production systems will be predicated on growers being able to access moths at an economically affordable quantity and price, as well as the ability to effectively and efficiently disseminate moths across their commercial production areas.