At a Glance
- Codling moth is a key pest of apples and pears.
- Larvae feed inside fruit, causing unmarketable damage.
- The pest can spread between blocks through bin movement and materials.
- Bins, firewood, and removed trees can carry overwintering populations.
- Monitoring and timing are critical for effective control.
- The BC DAS system supports decision‑making alongside trap data.
Why Is Codling Moth a Problem?
The codling moth is a common pest of apples and pears in the Okanagan Valley. Larvae feed within the fruit, causing damage that may appear as small stings or frass at exit holes on the fruit surface. This feeding makes fruit unmarketable and can significantly reduce pack‑out quality and financial returns.
Where Does Codling Moth Come From?
Codling moths overwinter in cocoons within orchards on tree trunks, bins, or wood piles. In spring, adults emerge, mate, and lay eggs on developing leaves and fruitlets. After approximately 10–14 days, larvae hatch and tunnel into fruit where they feed on seeds. Once inside the fruit, they are protected from many control measures. Pheromone traps are a key tool for monitoring codling moth populations. Information from trapping, including data collected by the Sterile Insect Release (SIR) program, helps growers assess population levels and determine the need for control.
Bin Movement and Spread Between Blocks
Codling moth can be spread between orchard blocks through the movement of bins, firewood, and removed trees. Materials originating from infested areas may contain overwintering larvae, allowing populations to be transported into clean or lower‑pressure orchards. Managing bin movement and handling orchard debris carefully can help reduce the risk of spreading codling moth between blocks and across growing regions.
How the BC DAS System Helps
The BC DAS system provides information on adult emergence and egg‑laying periods based on local orchard conditions. Using degree‑day accumulation and temperature data, the system predicts key development stages, including the start of egg laying at approximately 230 degree‑days. Combined with weather forecasts, the system helps identify optimal timing for control measures.
The DAS Spray Guide provides spray options, rates, and timing recommendations for codling moth management. Growers can plan programs with or without mating disruption (MD) and select products registered for conventional or organic use. Using BC DAS together with trapping information allows growers to make informed, timely decisions to reduce codling moth populations.
For more information, please check out the BC Tree Fruit Production Guide or contact the Okanagan-Kootenay Sterile Insect Release Program.
Learn More (Video)
Interested in finding out more? Check out the BC DAS Bin Movement and Codling Moth video to learn how orchard practices influence pest spread.