Sterile Moth Release Process

A major component of the SIR Program is the release of sterile codling moths into orchards.

• Understanding Sterile Insect Release (pdf)
• Recommended Timing for Codling Moth Cover Sprays in 2011 (pdf)

SIR begins with the mass rearing and sterilization of adult moths through gamma radiation at the Osoyoos, BC, facility.  Sterilized moths are delivered to orchards in plastic Petri dishes and kept cool so that they remain dormant.  Special devices mounted on 4-wheel ATVs release the moths into orchards in the service area on a weekly basis during the growing season.  The moths warm up and fly into the nearby host trees.  Over 200 millions sterile moths are released per year.

A successful sterile insect program requires that the sterile moth population overwhelm the wild, fertile, population, so that wild moths are likely to mate with a sterile moth, producing an infertile egg, and resulting in a decline in the codling moth population.

To be fully effective, sterile insect release must be applied over a large geographic area.  Good orchard sanitation must also be maintained, and reintroduction of wild codling moths into the area must be controlled or, ideally, prevented.

Sterile insect release is not a stand-alone method of control.  When wild codling moth populations are too high, growers will need to apply other control measures.