Growers can combat the destructive codling moth while promoting sustainability through the Sterile Insect Technique (SIT), a biological control method gaining popularity as a solution to this long-standing issue.
The codling moth, a major pest for apple, pear, and walnut orchards, can cause significant economic losses if left unchecked. Conventional control measures, such as broad-spectrum insecticides, have their limitations and can negatively impact beneficial insects and the environment. According to a report by the International Atomic Energy Agency, the OKSIR program in British Columbia has achieved significant reductions in codling moth populations and insecticide use, with less than 0.2% damage in over 90% of commercial pome fruit acreage.
What is the Sterile Insect Technique (SIT)?
SIT is a biological pest management method that involves mass-rearing and sterilizing codling moths before releasing them into orchards. The moths are sterilized with gamma irradiation, which renders them unable to produce viable offspring when they mate with wild moths. As the sterile moths outnumber the fertile population, the overall reproduction cycle is disrupted, leading to a gradual decline in pest numbers.
How SIT Works
The success of SIT hinges on several principles:
- Targeted Delivery: The sterile moths are imported from Osoyoos, BC and delivered to orchards in deli cups containing 3,200 sterilized male and female codling moth. These insects are then released into orchards via drones, ensuring precise and efficient distribution throughout the target area.
- Mass-Rearing and Sterilization: Facilities like the one in Osoyoos, BC, can produce up to 2 million sterilized moths per day, ensuring a consistent supply of sterile insects for release.
- Overwhelming the Wild Population: SIT requires the sterile moth population to overwhelm the wild, fertile population to be effective. This ratio of sterile to wild moths is critical for successful population suppression.
Implementing SIT for Codling Moth Control
While SIT can be a stand-alone method, it works best in conjunction with other control measures as a part of an Integrated Pest Management (IPM) program. This integrated approach combines SIT with techniques like mating disruption and selective sprays, gradually reducing the reliance on chemical inputs as the pest population declines.
Success stories from regions like British Columbia and parts of Washington demonstrate the real-world effectiveness of SIT in achieving near-zero codling moth pressure. Growers report better pest control and healthier orchards when SIT is applied consistently and in collaboration with neighbors, as codling moths don’t recognize orchard boundaries.
Economic and Environmental Benefits
Beyond its effectiveness in pest control, SIT offers compelling economic and environmental advantages:
- Cost-Effectiveness: At $400 per acre, SIT can reduce long-term costs and foster orchard health, especially in organic orchards where codling moth management can be very costly.
- Environmental Sustainability: Classical Sterile Insect Technique is an organic strategy that reduces reliance on broad-spectrum insecticides. SIT helps preserve beneficial insect communities and minimizes the risk of chemical residues on produce.
- Compatibility with Existing Tools: SIT is compatible with existing tools used in U.S. and Canadian production and can be integrated with other control methods like mating disruption and selective sprays, making it a valuable addition to integrated pest management (IPM) programs.
Looking Ahead
USDA Physicists (Left) Visit M3 Phoenix Module to discuss X-ray Biology Assays with Dr. Marion Le Gall (Right).
As the demand for sustainable agriculture practices grows, the role of SIT in codling moth control is poised to expand. Ongoing research at M3 Agriculture Technologies aims to further improve rearing techniques, sterile insect performance, and area-wide implementation strategies.
With its proven effectiveness, economic benefits, and environmental advantages, SIT offers a promising solution for growers seeking to balance productive yields with responsible stewardship of natural resources.
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